On Mon, 2021-09-06 at 09:35 +0200, Hans de Goede wrote:

From: Rajat Jain rajatja@google.com

Add support for generic electronic privacy screen properties, that can be added by systems that have an integrated EPS.

Changes in v2 (Hans de Goede)

• Create 2 properties, "privacy-screen sw-state" and

"privacy-screen hw-state", to deal with devices where the OS might be   locked out of making state changes

• Write kerneldoc explaining how the 2 properties work together, what

happens when changes to the state are made outside of the DRM code's   control, etc.

Changes in v3 (Hans de Goede)

• Some small tweaks to the kerneldoc describing the 2 properties

Changes in v4 (Hans de Goede)

• Change the "Enabled, locked" and "Disabled, locked" hw-state enum value

names to "Enabled-locked" and "Disabled-locked". The xrandr command shows   all possible enum values separated by commas in its output, so having a   comma in an enum name is not a good idea.

• Do not add a privacy_screen_hw_state member to drm_connector_state

since this property is immutable its value must be directly stored in the   obj->properties->values array

Signed-off-by: Rajat Jain rajatja@google.com Co-authored-by: Hans de Goede hdegoede@redhat.com Acked-by: Pekka Paalanen pekka.paalanen@collabora.com Reviewed-by: Mario Limonciello Mario.limonciello@dell.com Reviewed-by: Emil Velikov emil.l.velikov@gmail.com Signed-off-by: Hans de Goede hdegoede@redhat.com

---

Documentation/gpu/drm-kms.rst     |   2 +  drivers/gpu/drm/drm_atomic_uapi.c |   4 ++  drivers/gpu/drm/drm_connector.c   | 101 ++++++++++++++++++++++++++++++  include/drm/drm_connector.h       |  44 +++++++++++++  4 files changed, 151 insertions(+)

diff --git a/Documentation/gpu/drm-kms.rst b/Documentation/gpu/drm-kms.rst index 1ef7951ded5e..d14bf1c35d7e 100644 --- a/Documentation/gpu/drm-kms.rst +++ b/Documentation/gpu/drm-kms.rst @@ -506,6 +506,8 @@ Property Types and Blob Property Support  .. kernel-doc:: drivers/gpu/drm/drm_property.c     :export:   +.. _standard_connector_properties:

Standard Connector Properties  -----------------------------   diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c index 909f31833181..cdd31fc78bfc 100644 --- a/drivers/gpu/drm/drm_atomic_uapi.c +++ b/drivers/gpu/drm/drm_atomic_uapi.c @@ -797,6 +797,8 @@ static int drm_atomic_connector_set_property(struct drm_connector *connector,                                                    fence_ptr);         } else if (property == connector->max_bpc_property) {                 state->max_requested_bpc = val; +       } else if (property == connector->privacy_screen_sw_state_property) { +               state->privacy_screen_sw_state = val;         } else if (connector->funcs->atomic_set_property) {                 return connector->funcs->atomic_set_property(connector,                                 state, property, val); @@ -874,6 +876,8 @@ drm_atomic_connector_get_property(struct drm_connector *connector,                 *val = 0;         } else if (property == connector->max_bpc_property) {                 *val = state->max_requested_bpc; +       } else if (property == connector->privacy_screen_sw_state_property) { +               *val = state->privacy_screen_sw_state;         } else if (connector->funcs->atomic_get_property) {                 return connector->funcs->atomic_get_property(connector,                                 state, property, val); diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c index e0a30e0ee86a..dd1ca68881ba 100644 --- a/drivers/gpu/drm/drm_connector.c +++ b/drivers/gpu/drm/drm_connector.c @@ -1264,6 +1264,46 @@ static const struct drm_prop_enum_list dp_colorspaces[] = {   *     For DVI-I and TVout there is also a matching property "select subconnector"   *     allowing to switch between signal types.   *     DP subconnector corresponds to a downstream port.

• • privacy-screen sw-state, privacy-screen hw-state:
• *     These 2 optional properties can be used to query the state of the
• *     electronic privacy screen that is available on some displays; and in
• *     some cases also control the state. If a driver implements these
• *     properties then both properties must be present.
• *     "privacy-screen hw-state" is read-only and reflects the actual state
• *     of the privacy-screen, possible values: "Enabled", "Disabled,
• *     "Enabled-locked", "Disabled-locked". The locked states indicate
• *     that the state cannot be changed through the DRM API. E.g. there
• *     might be devices where the firmware-setup options, or a hardware
• *     slider-switch, offer always on / off modes.
• *     "privacy-screen sw-state" can be set to change the privacy-screen

state

• *     when not locked. In this case the driver must update the hw-state
• *     property to reflect the new state on completion of the commit of the
• *     sw-state property. Setting the sw-state property when the hw-state

is

• *     locked must be interpreted by the driver as a request to change the
• *     state to the set state when the hw-state becomes unlocked. E.g. if
• *     "privacy-screen hw-state" is "Enabled-locked" and the sw-state
• *     gets set to "Disabled" followed by the user unlocking the state by
• *     changing the slider-switch position, then the driver must set the
• *     state to "Disabled" upon receiving the unlock event.
• *     In some cases the privacy-screen's actual state might change outside

of

• *     control of the DRM code. E.g. there might be a firmware handled

hotkey

• *     which toggles the actual state, or the actual state might be changed
• *     through another userspace API such as writing

/proc/acpi/ibm/lcdshadow.

• *     In this case the driver must update both the hw-state and the sw-

state

• *     to reflect the new value, overwriting any pending state requests in

the

• *     sw-state. Any pending sw-state requests are thus discarded.
• *     Note that the ability for the state to change outside of control of
• *     the DRM master process means that userspace must not cache the value
• *     of the sw-state. Caching the sw-state value and including it in

later

• *     atomic commits may lead to overriding a state change done through

e.g.

• *     a firmware handled hotkey. Therefor userspace must not include the
• *     privacy-screen sw-state in an atomic commit unless it wants to

change

• *     its value.

*/    int drm_connector_create_standard_properties(struct drm_device *dev) @@ -2341,6 +2381,67 @@ int drm_connector_set_panel_orientation_with_quirk(  }  EXPORT_SYMBOL(drm_connector_set_panel_orientation_with_quirk);   +static const struct drm_prop_enum_list privacy_screen_enum[] = { +       { PRIVACY_SCREEN_DISABLED,              "Disabled" }, +       { PRIVACY_SCREEN_ENABLED,               "Enabled" }, +       { PRIVACY_SCREEN_DISABLED_LOCKED,       "Disabled-locked" }, +       { PRIVACY_SCREEN_ENABLED_LOCKED,        "Enabled-locked" }, +};

+/**

• • drm_connector_create_privacy_screen_properties - create the drm

connecter's

• *    privacy-screen properties.
• • @connector: connector for which to create the privacy-screen properties
• • This function creates the "privacy-screen sw-state" and "privacy-screen
• • hw-state" properties for the connector. They are not attached.
• */

+void +drm_connector_create_privacy_screen_properties(struct drm_connector *connector) +{ +       if (connector->privacy_screen_sw_state_property) +               return;

+       /* Note sw-state only supports the first 2 values of the enum */ +       connector->privacy_screen_sw_state_property = +               drm_property_create_enum(connector->dev, DRM_MODE_PROP_ENUM, +                               "privacy-screen sw-state", +                               privacy_screen_enum, 2);

+       connector->privacy_screen_hw_state_property = +               drm_property_create_enum(connector->dev, +                               DRM_MODE_PROP_IMMUTABLE | DRM_MODE_PROP_ENUM, +                               "privacy-screen hw-state", +                               privacy_screen_enum, +                               ARRAY_SIZE(privacy_screen_enum)); +} +EXPORT_SYMBOL(drm_connector_create_privacy_screen_properties);

+/**

• • drm_connector_attach_privacy_screen_properties - attach the drm

connecter's

• *    privacy-screen properties.
• • @connector: connector on which to attach the privacy-screen properties
• • This function attaches the "privacy-screen sw-state" and "privacy-screen
• • hw-state" properties to the connector. The initial state of both is set
• • to "Disabled".
• */

+void +drm_connector_attach_privacy_screen_properties(struct drm_connector *connector) +{ +       if (!connector->privacy_screen_sw_state_property) +               return;

+       drm_object_attach_property(&connector->base, +                                  connector-

...

privacy_screen_sw_state_property,

+                                  PRIVACY_SCREEN_DISABLED);

+       drm_object_attach_property(&connector->base, +                                  connector-

...

privacy_screen_hw_state_property,

+                                  PRIVACY_SCREEN_DISABLED); +} +EXPORT_SYMBOL(drm_connector_attach_privacy_screen_properties);

int drm_connector_set_obj_prop(struct drm_mode_object *obj,                                     struct drm_property *property,                                     uint64_t value) diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h index 79fa34e5ccdb..1acbcf0626ce 100644 --- a/include/drm/drm_connector.h +++ b/include/drm/drm_connector.h @@ -320,6 +320,30 @@ struct drm_monitor_range_info {         u8 max_vfreq;  };   +/**

• • enum drm_privacy_screen_status - privacy screen status
• • This enum is used to track and control the state of the integrated

privacy

• • screen present on some display panels, via the "privacy-screen sw-state"
• • and "privacy-screen hw-state" properties. Note the _LOCKED enum values
• • are only valid for the "privacy-screen hw-state" property.
• • @PRIVACY_SCREEN_DISABLED:
• *  The privacy-screen on the panel is disabled
• • @PRIVACY_SCREEN_ENABLED:
• *  The privacy-screen on the panel is enabled
• • @PRIVACY_SCREEN_DISABLED_LOCKED:
• *  The privacy-screen on the panel is disabled and locked (cannot be

changed)

• • @PRIVACY_SCREEN_ENABLED_LOCKED:
• *  The privacy-screen on the panel is enabled and locked (cannot be

changed)

• */

+enum drm_privacy_screen_status { +       PRIVACY_SCREEN_DISABLED = 0, +       PRIVACY_SCREEN_ENABLED, +       PRIVACY_SCREEN_DISABLED_LOCKED, +       PRIVACY_SCREEN_ENABLED_LOCKED, +};

/*   * This is a consolidated colorimetry list supported by HDMI and   * DP protocol standard. The respective connectors will register @@ -781,6 +805,12 @@ struct drm_connector_state {          */         u8 max_bpc;   +       /** +        * @privacy_screen_sw_state: See :ref:`Standard Connector +        * Properties<standard_connector_properties>` +        */

So THAT'S how you reference other sections. I've always wondered!

+       enum drm_privacy_screen_status privacy_screen_sw_state;

/**          * @hdr_output_metadata:          * DRM blob property for HDR output metadata @@ -1409,6 +1439,18 @@ struct drm_connector {          */         struct drm_property *max_bpc_property;   +       /** +        * @privacy_screen_sw_state_property: Optional atomic property for the +        * connector to control the integrated privacy screen. +        */ +       struct drm_property *privacy_screen_sw_state_property;

+       /** +        * @privacy_screen_hw_state_property: Optional atomic property for the +        * connector to report the actual integrated privacy screen state. +        */ +       struct drm_property *privacy_screen_hw_state_property;

#define DRM_CONNECTOR_POLL_HPD (1 << 0)  #define DRM_CONNECTOR_POLL_CONNECT (1 << 1)  #define DRM_CONNECTOR_POLL_DISCONNECT (1 << 2) @@ -1732,6 +1774,8 @@ int drm_connector_set_panel_orientation_with_quirk(         int width, int height);  int drm_connector_attach_max_bpc_property(struct drm_connector *connector,                                           int min, int max); +void drm_connector_create_privacy_screen_properties(struct drm_connector *conn); +void drm_connector_attach_privacy_screen_properties(struct drm_connector *conn);    /**   * struct drm_tile_group - Tile group metadata

Hi Lyude,

Thank you very much for the review of this series.

On 9/15/21 10:01 PM, Lyude Paul wrote:

On Mon, 2021-09-06 at 09:35 +0200, Hans de Goede wrote:

...

On some new laptops the LCD panel has a builtin electronic privacy-screen. We want to export this functionality as a property on the drm connector object. But often this functionality is not exposed on the GPU but on some other (ACPI) device.

This commit adds a privacy-screen class allowing the driver for these other devices to register themselves as a privacy-screen provider; and allowing the drm/kms code to get a privacy-screen provider associated with a specific GPU/connector combo.

Changes in v2:

• Make CONFIG_DRM_PRIVACY_SCREEN a bool which controls if the drm_privacy

code gets built as part of the main drm module rather then making it   a tristate which builds its own module.

• Add a #if IS_ENABLED(CONFIG_DRM_PRIVACY_SCREEN) check to

drm_privacy_screen_consumer.h and define stubs when the check fails.   Together these 2 changes fix several dependency issues.

• Remove module related code now that this is part of the main drm.ko
• Use drm_class as class for the privacy-screen devices instead of

adding a separate class for this

Changes in v3:

• Make the static inline drm_privacy_screen_get_state() stub set sw_state

and hw_state to PRIVACY_SCREEN_DISABLED to squelch an uninitialized   variable warning when CONFIG_DRM_PRIVICAY_SCREEN is not set

Reviewed-by: Emil Velikov emil.l.velikov@gmail.com Signed-off-by: Hans de Goede hdegoede@redhat.com

---

Documentation/gpu/drm-kms-helpers.rst     |  15 +  MAINTAINERS                               |   8 +  drivers/gpu/drm/Kconfig                   |   4 +  drivers/gpu/drm/Makefile                  |   1 +  drivers/gpu/drm/drm_drv.c                 |   4 +  drivers/gpu/drm/drm_privacy_screen.c      | 401 ++++++++++++++++++++++  include/drm/drm_privacy_screen_consumer.h |  50 +++  include/drm/drm_privacy_screen_driver.h   |  80 +++++  include/drm/drm_privacy_screen_machine.h  |  41 +++  9 files changed, 604 insertions(+)  create mode 100644 drivers/gpu/drm/drm_privacy_screen.c  create mode 100644 include/drm/drm_privacy_screen_consumer.h  create mode 100644 include/drm/drm_privacy_screen_driver.h  create mode 100644 include/drm/drm_privacy_screen_machine.h

diff --git a/Documentation/gpu/drm-kms-helpers.rst b/Documentation/gpu/drm- kms-helpers.rst index 389892f36185..5d8715d2f998 100644 --- a/Documentation/gpu/drm-kms-helpers.rst +++ b/Documentation/gpu/drm-kms-helpers.rst @@ -423,3 +423,18 @@ Legacy CRTC/Modeset Helper Functions Reference    .. kernel-doc:: drivers/gpu/drm/drm_crtc_helper.c     :export:

+Privacy-screen class +====================

+.. kernel-doc:: drivers/gpu/drm/drm_privacy_screen.c +   :doc: overview

+.. kernel-doc:: include/drm/drm_privacy_screen_driver.h +   :internal:

+.. kernel-doc:: include/drm/drm_privacy_screen_machine.h +   :internal:

+.. kernel-doc:: drivers/gpu/drm/drm_privacy_screen.c +   :export: diff --git a/MAINTAINERS b/MAINTAINERS index ede4a37a53b3..a272ca600f98 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -6376,6 +6376,14 @@ F:       drivers/gpu/drm/drm_panel.c  F:     drivers/gpu/drm/panel/  F:     include/drm/drm_panel.h   +DRM PRIVACY-SCREEN CLASS +M:     Hans de Goede hdegoede@redhat.com +L:     dri-devel@lists.freedesktop.org +S:     Maintained +T:     git git://anongit.freedesktop.org/drm/drm-misc +F:     drivers/gpu/drm/drm_privacy_screen* +F:     include/drm/drm_privacy_screen*

DRM TTM SUBSYSTEM  M:     Christian Koenig christian.koenig@amd.com  M:     Huang Rui ray.huang@amd.com diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig index b17e231ca6f7..7249b010ab90 100644 --- a/drivers/gpu/drm/Kconfig +++ b/drivers/gpu/drm/Kconfig @@ -481,3 +481,7 @@ config DRM_PANEL_ORIENTATION_QUIRKS  config DRM_LIB_RANDOM         bool         default n

+config DRM_PRIVACY_SCREEN +       bool +       default n

This is probably worth documenting for folks configuring their kernels to explain what this actually does (something simple like "Controls programmable privacy screens found on some devices, if unsure select Y" would probably be fine)

Like the "config DRM_LIB_RANDOM" above it, this is not user selectable, (notice there is no text after the "bool"), this is selected by drivers which implement drm-privacy-screen control, such as the thinkpad_acpi driver.

If no such drivers is selected and thus CONFIG_DRM_PRIVACY_SCREEN is not enabled then include/drm/drm_privacy_screen_consumer.h and drm_privacy_screen_machine.h provide no-op stubs so that the integration with the drm-core still builds without needing #ifdef-s in the drm-core.

...

diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile index 0dff40bb863c..788fc37096f6 100644 --- a/drivers/gpu/drm/Makefile +++ b/drivers/gpu/drm/Makefile @@ -32,6 +32,7 @@ drm-$(CONFIG_OF) += drm_of.o  drm-$(CONFIG_PCI) += drm_pci.o  drm-$(CONFIG_DEBUG_FS) += drm_debugfs.o drm_debugfs_crc.o  drm-$(CONFIG_DRM_LOAD_EDID_FIRMWARE) += drm_edid_load.o +drm-$(CONFIG_DRM_PRIVACY_SCREEN) += drm_privacy_screen.o    obj-$(CONFIG_DRM_DP_AUX_BUS) += drm_dp_aux_bus.o   diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c index 7a5097467ba5..dc293b771c3f 100644 --- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -43,6 +43,7 @@  #include <drm/drm_managed.h>  #include <drm/drm_mode_object.h>  #include <drm/drm_print.h> +#include <drm/drm_privacy_screen_machine.h>    #include "drm_crtc_internal.h"  #include "drm_internal.h" @@ -1029,6 +1030,7 @@ static const struct file_operations drm_stub_fops = {    static void drm_core_exit(void)  { +       drm_privacy_screen_lookup_exit();         unregister_chrdev(DRM_MAJOR, "drm");         debugfs_remove(drm_debugfs_root);         drm_sysfs_destroy(); @@ -1056,6 +1058,8 @@ static int __init drm_core_init(void)         if (ret < 0)                 goto error;   +       drm_privacy_screen_lookup_init();

drm_core_init_complete = true;           DRM_DEBUG("Initialized\n"); diff --git a/drivers/gpu/drm/drm_privacy_screen.c b/drivers/gpu/drm/drm_privacy_screen.c new file mode 100644 index 000000000000..294a09194bfb --- /dev/null +++ b/drivers/gpu/drm/drm_privacy_screen.c @@ -0,0 +1,401 @@ +// SPDX-License-Identifier: MIT +/*

• • Copyright (C) 2020 - 2021 Red Hat, Inc.
• • Authors:
• • Hans de Goede hdegoede@redhat.com
• */

+#include <linux/device.h> +#include <linux/kernel.h> +#include <linux/list.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/slab.h> +#include <drm/drm_privacy_screen_machine.h> +#include <drm/drm_privacy_screen_consumer.h> +#include <drm/drm_privacy_screen_driver.h> +#include "drm_internal.h"

+/**

• • DOC: overview
• • This class allows non KMS drivers, from e.g. drivers/platform/x86 to
• • register a privacy-screen device, which the KMS drivers can then use
• • to implement the standard privacy-screen properties, see
• • :ref:`Standard Connector Properties<standard_connector_properties>`.
• • KMS drivers using a privacy-screen class device are advised to use the
• • drm_connector_attach_privacy_screen_provider() and
• • drm_connector_update_privacy_screen() helpers for dealing with this.
• */

+#define to_drm_privacy_screen(dev) \ +       container_of(dev, struct drm_privacy_screen, dev)

+static DEFINE_MUTEX(drm_privacy_screen_lookup_lock); +static LIST_HEAD(drm_privacy_screen_lookup_list);

+static DEFINE_MUTEX(drm_privacy_screen_devs_lock); +static LIST_HEAD(drm_privacy_screen_devs);

+/*** drm_privacy_screen_machine.h functions ***/

+/**

• • drm_privacy_screen_lookup_add - add an entry to the static privacy-

screen

• *    lookup list
• • @lookup: lookup list entry to add
• • Add an entry to the static privacy-screen lookup list. Note the
• • &struct list_head which is part of the &struct drm_privacy_screen_lookup
• • gets added to a list owned by the privacy-screen core. So the passed in
• • &struct drm_privacy_screen_lookup must not be free-ed until it is

removed

• • from the lookup list by calling drm_privacy_screen_lookup_remove().
• */

+void drm_privacy_screen_lookup_add(struct drm_privacy_screen_lookup *lookup) +{ +       mutex_lock(&drm_privacy_screen_lookup_lock); +       list_add(&lookup->list, &drm_privacy_screen_lookup_list); +       mutex_unlock(&drm_privacy_screen_lookup_lock); +} +EXPORT_SYMBOL(drm_privacy_screen_lookup_add);

+/**

• • drm_privacy_screen_lookup_remove - remove an entry to the static
• *    privacy-screen lookup list
• • @lookup: lookup list entry to remove
• • Remove an entry previously added with drm_privacy_screen_lookup_add()
• • from the static privacy-screen lookup list.
• */

+void drm_privacy_screen_lookup_remove(struct drm_privacy_screen_lookup *lookup) +{ +       mutex_lock(&drm_privacy_screen_lookup_lock); +       list_del(&lookup->list); +       mutex_unlock(&drm_privacy_screen_lookup_lock); +} +EXPORT_SYMBOL(drm_privacy_screen_lookup_remove);

+/*** drm_privacy_screen_consumer.h functions ***/

+static struct drm_privacy_screen *drm_privacy_screen_get_by_name( +       const char *name) +{ +       struct drm_privacy_screen *priv; +       struct device *dev = NULL;

+       mutex_lock(&drm_privacy_screen_devs_lock);

+       list_for_each_entry(priv, &drm_privacy_screen_devs, list) { +               if (strcmp(dev_name(&priv->dev), name) == 0) { +                       dev = get_device(&priv->dev); +                       break; +               } +       }

+       mutex_unlock(&drm_privacy_screen_devs_lock);

+       return dev ? to_drm_privacy_screen(dev) : NULL; +}

+/**

• • drm_privacy_screen_get - get a privacy-screen provider
• • @dev: consumer-device for which to get a privacy-screen provider
• • @con_id: (video)connector name for which to get a privacy-screen

provider

• • Get a privacy-screen provider for a privacy-screen attached to the
• • display described by the @dev and @con_id parameters.
• • Return:
• • • A pointer to a &struct drm_privacy_screen on success.
• • • ERR_PTR(-ENODEV) if no matching privacy-screen is found
• • • ERR_PTR(-EPROBE_DEFER) if there is a matching privacy-screen,
• *                          but it has not been registered yet.
• */

+struct drm_privacy_screen *drm_privacy_screen_get(struct device *dev, +                                                 const char *con_id) +{ +       const char *dev_id = dev ? dev_name(dev) : NULL; +       struct drm_privacy_screen_lookup *l; +       struct drm_privacy_screen *priv; +       const char *provider = NULL; +       int match, best = -1;

+       /* +        * For now we only support using a static lookup table, which is +        * populated by the drm_privacy_screen_arch_init() call. This should +        * be extended with device-tree / fw_node lookup when support is added +        * for device-tree using hardware with a privacy-screen. +        * +        * The lookup algorithm was shamelessly taken from the clock +        * framework: +        * +        * We do slightly fuzzy matching here: +        *  An entry with a NULL ID is assumed to be a wildcard. +        *  If an entry has a device ID, it must match +        *  If an entry has a connection ID, it must match +        * Then we take the most specific entry - with the following order +        * of precedence: dev+con > dev only > con only. +        */ +       mutex_lock(&drm_privacy_screen_lookup_lock);

+       list_for_each_entry(l, &drm_privacy_screen_lookup_list, list) { +               match = 0;

+               if (l->dev_id) { +                       if (!dev_id || strcmp(l->dev_id, dev_id)) +                               continue;

+                       match += 2; +               }

+               if (l->con_id) { +                       if (!con_id || strcmp(l->con_id, con_id)) +                               continue;

+                       match += 1; +               }

+               if (match > best) { +                       provider = l->provider; +                       best = match; +               } +       }

+       mutex_unlock(&drm_privacy_screen_lookup_lock);

+       if (!provider) +               return ERR_PTR(-ENODEV);

+       priv = drm_privacy_screen_get_by_name(provider); +       if (!priv) +               return ERR_PTR(-EPROBE_DEFER);

+       return priv; +} +EXPORT_SYMBOL(drm_privacy_screen_get);

+/**

• • drm_privacy_screen_put - release a privacy-screen reference
• • @priv: privacy screen reference to release
• • Release a privacy-screen provider reference gotten through
• • drm_privacy_screen_get(). May be called with a NULL or ERR_PTR,
• • in which case it is a no-op.
• */

+void drm_privacy_screen_put(struct drm_privacy_screen *priv) +{ +       if (IS_ERR_OR_NULL(priv)) +               return;

+       put_device(&priv->dev); +} +EXPORT_SYMBOL(drm_privacy_screen_put);

+/**

• • drm_privacy_screen_set_sw_state - set a privacy-screen's sw-state
• • @priv: privacy screen to set the sw-state for
• • @sw_state: new sw-state value to set
• • Set the sw-state of a privacy screen. If the privacy-screen is not
• • in a locked hw-state, then the actual and hw-state of the privacy-screen
• • will be immediately updated to the new value. If the privacy-screen is
• • in a locked hw-state, then the new sw-state will be remembered as the
• • requested state to put the privacy-screen in when it becomes unlocked.
• • Return: 0 on success, negative error code on failure.
• */

+int drm_privacy_screen_set_sw_state(struct drm_privacy_screen *priv, +                                   enum drm_privacy_screen_status sw_state) +{ +       int ret = 0;

+       mutex_lock(&priv->lock);

+       if (!priv->ops) { +               ret = -ENODEV; +               goto out; +       }

+       /* +        * As per the DRM connector properties documentation, setting the +        * sw_state while the hw_state is locked is allowed. In this case +        * it is a no-op other then storing the new sw_state so that it +        * can be honored when the state gets unlocked. +        */ +       if (priv->hw_state >= PRIVACY_SCREEN_DISABLED_LOCKED) { +               priv->sw_state = sw_state; +               goto out; +       }

+       ret = priv->ops->set_sw_state(priv, sw_state); +out: +       mutex_unlock(&priv->lock); +       return ret; +} +EXPORT_SYMBOL(drm_privacy_screen_set_sw_state);

+/**

• • drm_privacy_screen_get_state - get privacy-screen's current state
• • @priv: privacy screen to get the state for
• • @sw_state_ret: address where to store the privacy-screens current sw-

state

• • @hw_state_ret: address where to store the privacy-screens current hw-

state

• • Get the current state of a privacy-screen, both the sw-state and the
• • hw-state.
• */

+void drm_privacy_screen_get_state(struct drm_privacy_screen *priv, +                                 enum drm_privacy_screen_status *sw_state_ret, +                                 enum drm_privacy_screen_status *hw_state_ret) +{ +       mutex_lock(&priv->lock); +       *sw_state_ret = priv->sw_state; +       *hw_state_ret = priv->hw_state; +       mutex_unlock(&priv->lock); +} +EXPORT_SYMBOL(drm_privacy_screen_get_state);

+/*** drm_privacy_screen_driver.h functions ***/

+static ssize_t sw_state_show(struct device *dev, +                            struct device_attribute *attr, char *buf) +{ +       struct drm_privacy_screen *priv = to_drm_privacy_screen(dev); +       const char * const sw_state_names[] = { +               "Disabled", +               "Enabled", +       }; +       ssize_t ret;

+       mutex_lock(&priv->lock);

+       if (!priv->ops) +               ret = -ENODEV; +       else if (WARN_ON(priv->sw_state >= ARRAY_SIZE(sw_state_names))) +               ret = -ENXIO; +       else +               ret = sprintf(buf, "%s\n", sw_state_names[priv->sw_state]);

+       mutex_unlock(&priv->lock); +       return ret; +} +/*

• • RO: Do not allow setting the sw_state through sysfs, this MUST be done
• • through the drm_properties on the drm_connector.
• */

+static DEVICE_ATTR_RO(sw_state);

+static ssize_t hw_state_show(struct device *dev, +                            struct device_attribute *attr, char *buf) +{ +       struct drm_privacy_screen *priv = to_drm_privacy_screen(dev); +       const char * const hw_state_names[] = { +               "Disabled", +               "Enabled", +               "Disabled, locked", +               "Enabled, locked", +       }; +       ssize_t ret;

+       mutex_lock(&priv->lock);

+       if (!priv->ops) +               ret = -ENODEV; +       else if (WARN_ON(priv->hw_state >= ARRAY_SIZE(hw_state_names))) +               ret = -ENXIO; +       else +               ret = sprintf(buf, "%s\n", hw_state_names[priv->hw_state]);

+       mutex_unlock(&priv->lock); +       return ret; +} +static DEVICE_ATTR_RO(hw_state);

+static struct attribute *drm_privacy_screen_attrs[] = { +       &dev_attr_sw_state.attr, +       &dev_attr_hw_state.attr, +       NULL +}; +ATTRIBUTE_GROUPS(drm_privacy_screen);

+static struct device_type drm_privacy_screen_type = { +       .name = "privacy_screen", +       .groups = drm_privacy_screen_groups, +};

+static void drm_privacy_screen_device_release(struct device *dev) +{ +       struct drm_privacy_screen *priv = to_drm_privacy_screen(dev);

+       kfree(priv); +}

+/**

• • drm_privacy_screen_register - register a privacy-screen
• • @parent: parent-device for the privacy-screen
• • @ops: &struct drm_privacy_screen_ops pointer with ops for the privacy-

screen

• • Create and register a privacy-screen.
• • Return:
• • • A pointer to the created privacy-screen on success.
• • • An ERR_PTR(errno) on failure.
• */

+struct drm_privacy_screen *drm_privacy_screen_register( +       struct device *parent, const struct drm_privacy_screen_ops *ops) +{ +       struct drm_privacy_screen *priv; +       int ret;

+       priv = kzalloc(sizeof(*priv), GFP_KERNEL); +       if (!priv) +               return ERR_PTR(-ENOMEM);

+       mutex_init(&priv->lock);

+       priv->dev.class = drm_class; +       priv->dev.type = &drm_privacy_screen_type; +       priv->dev.parent = parent; +       priv->dev.release = drm_privacy_screen_device_release; +       dev_set_name(&priv->dev, "privacy_screen-%s", dev_name(parent)); +       priv->ops = ops;

+       priv->ops->get_hw_state(priv);

+       ret = device_register(&priv->dev); +       if (ret) { +               put_device(&priv->dev); +               return ERR_PTR(ret); +       }

+       mutex_lock(&drm_privacy_screen_devs_lock); +       list_add(&priv->list, &drm_privacy_screen_devs); +       mutex_unlock(&drm_privacy_screen_devs_lock);

+       return priv; +} +EXPORT_SYMBOL(drm_privacy_screen_register);

+/**

• • drm_privacy_screen_unregister - unregister privacy-screen
• • @priv: privacy-screen to unregister
• • Unregister a privacy-screen registered with

drm_privacy_screen_register().

• • May be called with a NULL or ERR_PTR, in which case it is a no-op.
• */

+void drm_privacy_screen_unregister(struct drm_privacy_screen *priv) +{ +       if (IS_ERR_OR_NULL(priv)) +               return;

+       mutex_lock(&drm_privacy_screen_devs_lock); +       list_del(&priv->list); +       mutex_unlock(&drm_privacy_screen_devs_lock);

+       mutex_lock(&priv->lock); +       priv->ops = NULL; +       mutex_unlock(&priv->lock);

+       device_unregister(&priv->dev); +} +EXPORT_SYMBOL(drm_privacy_screen_unregister); diff --git a/include/drm/drm_privacy_screen_consumer.h b/include/drm/drm_privacy_screen_consumer.h new file mode 100644 index 000000000000..0cbd23b0453d --- /dev/null +++ b/include/drm/drm_privacy_screen_consumer.h @@ -0,0 +1,50 @@ +/* SPDX-License-Identifier: MIT */ +/*

• • Copyright (C) 2020 Red Hat, Inc.
• • Authors:
• • Hans de Goede hdegoede@redhat.com
• */

+#ifndef __DRM_PRIVACY_SCREEN_CONSUMER_H__ +#define __DRM_PRIVACY_SCREEN_CONSUMER_H__

+#include <linux/device.h> +#include <drm/drm_connector.h>

+struct drm_privacy_screen;

+#if IS_ENABLED(CONFIG_DRM_PRIVACY_SCREEN) +struct drm_privacy_screen *drm_privacy_screen_get(struct device *dev, +                                                 const char *con_id); +void drm_privacy_screen_put(struct drm_privacy_screen *priv);

+int drm_privacy_screen_set_sw_state(struct drm_privacy_screen *priv, +                                   enum drm_privacy_screen_status sw_state); +void drm_privacy_screen_get_state(struct drm_privacy_screen *priv, +                                 enum drm_privacy_screen_status *sw_state_ret, +                                 enum drm_privacy_screen_status *hw_state_ret); +#else +static inline struct drm_privacy_screen *drm_privacy_screen_get(struct device *dev, +                                                               const char *con_id) +{ +       return ERR_PTR(-ENODEV); +} +static inline void drm_privacy_screen_put(struct drm_privacy_screen *priv) +{ +} +static inline int drm_privacy_screen_set_sw_state(struct drm_privacy_screen *priv, +                                                 enum drm_privacy_screen_status sw_state) +{ +       return -ENODEV; +} +static inline void drm_privacy_screen_get_state(struct drm_privacy_screen *priv, +                                               enum drm_privacy_screen_status *sw_state_ret, +                                               enum drm_privacy_screen_status *hw_state_ret) +{ +       *sw_state_ret = PRIVACY_SCREEN_DISABLED; +       *hw_state_ret = PRIVACY_SCREEN_DISABLED; +} +#endif

+#endif diff --git a/include/drm/drm_privacy_screen_driver.h b/include/drm/drm_privacy_screen_driver.h new file mode 100644 index 000000000000..5187ae52eb03 --- /dev/null +++ b/include/drm/drm_privacy_screen_driver.h @@ -0,0 +1,80 @@ +/* SPDX-License-Identifier: MIT */ +/*

• • Copyright (C) 2020 Red Hat, Inc.
• • Authors:
• • Hans de Goede hdegoede@redhat.com
• */

+#ifndef __DRM_PRIVACY_SCREEN_DRIVER_H__ +#define __DRM_PRIVACY_SCREEN_DRIVER_H__

+#include <linux/device.h> +#include <linux/list.h> +#include <linux/mutex.h> +#include <drm/drm_connector.h>

+struct drm_privacy_screen;

+/**

• • struct drm_privacy_screen_ops - drm_privacy_screen operations
• • Defines the operations which the privacy-screen class code may call.
• • These functions should be implemented by the privacy-screen driver.
• */

+struct drm_privacy_screen_ops { +       /** +        * @set_sw_state: Called to request a change of the privacy-screen +        * state. The privacy-screen class code contains a check to avoid this +        * getting called when the hw_state reports the state is locked. +        * It is the driver's responsibility to update sw_state and hw_state. +        * This is always called with the drm_privacy_screen's lock held. +        */ +       int (*set_sw_state)(struct drm_privacy_screen *priv, +                           enum drm_privacy_screen_status sw_state); +       /** +        * @get_hw_state: Called to request that the driver gets the current +        * privacy-screen state from the hardware and then updates sw_state and +        * hw_state accordingly. This will be called by the core just before +        * the privacy-screen is registered in sysfs. +        */ +       void (*get_hw_state)(struct drm_privacy_screen *priv); +};

+/**

• • struct drm_privacy_screen - central privacy-screen structure
• • Central privacy-screen structure, this contains the struct device used
• • to register the screen in sysfs, the screen's state, ops, etc.
• */

+struct drm_privacy_screen { +       /** @dev: device used to register the privacy-screen in sysfs. */ +       struct device dev; +       /** @lock: mutex protection all fields in this struct. */ +       struct mutex lock; +       /** @list: privacy-screen devices list list-entry. */ +       struct list_head list; +       /** +        * @ops: &struct drm_privacy_screen_ops for this privacy-screen. +        * This is NULL if the driver has unregistered the privacy-screen. +        */ +       const struct drm_privacy_screen_ops *ops; +       /** +        * @sw_state: The privacy-screen's software state, see +        * :ref:`Standard Connector Properties<standard_connector_properties>` +        * for more info. +        */ +       enum drm_privacy_screen_status sw_state; +       /** +        * @hw_state: The privacy-screen's hardware state, see +        * :ref:`Standard Connector Properties<standard_connector_properties>` +        * for more info. +        */ +       enum drm_privacy_screen_status hw_state; +};

+struct drm_privacy_screen *drm_privacy_screen_register( +       struct device *parent, const struct drm_privacy_screen_ops *ops); +void drm_privacy_screen_unregister(struct drm_privacy_screen *priv);

+#endif diff --git a/include/drm/drm_privacy_screen_machine.h b/include/drm/drm_privacy_screen_machine.h new file mode 100644 index 000000000000..aaa0d38cce92 --- /dev/null +++ b/include/drm/drm_privacy_screen_machine.h @@ -0,0 +1,41 @@ +/* SPDX-License-Identifier: MIT */ +/*

• • Copyright (C) 2020 Red Hat, Inc.
• • Authors:
• • Hans de Goede hdegoede@redhat.com
• */

+#ifndef __DRM_PRIVACY_SCREEN_MACHINE_H__ +#define __DRM_PRIVACY_SCREEN_MACHINE_H__

+#include <linux/list.h>

+/**

• • struct drm_privacy_screen_lookup -  static privacy-screen lookup list

entry

• • Used for the static lookup-list for mapping privacy-screen consumer
• • dev-connector pairs to a privacy-screen provider.
• */

+struct drm_privacy_screen_lookup { +       /** @list: Lookup list list-entry. */ +       struct list_head list; +       /** @dev_id: Consumer device name or NULL to match all devices. */ +       const char *dev_id; +       /** @con_id: Consumer connector name or NULL to match all connectors. */

I think this patch mostly looks good, the one part that I'm a little confused on here is the con_id. Perhaps I missed this when looking over this patch, but what "connector name" are we referring to here - the DRM connector name (e.g. eDP-1), or something else?

Yes con_id refers to the DRM connector name.

The reason I ask is because I wonder if connector names are really the way that we want to be looking DRM connectors up, since I believe it's possible for two different GPUs to have DRM connectors with the same name.

Right this is why the lookup matches on both the GPU's (consumer's (1)) dev_name and the con_id, the combination of these should always by unique.

I hope this helps explain how this is intended to work (and works on the ThinkPad T14 gen 1 which I have tested this on).

Regards,

Hans

1) The consumer is the GPU device/driver which wants to tie a drm-privacy-screen control provider to a LCD-panel output.

...

+       const char *con_id; +       /** @provider: dev_name() of the privacy_screen provider. */ +       const char *provider; +};

+void drm_privacy_screen_lookup_add(struct drm_privacy_screen_lookup *lookup); +void drm_privacy_screen_lookup_remove(struct drm_privacy_screen_lookup *lookup);

+static inline void drm_privacy_screen_lookup_init(void) +{ +} +static inline void drm_privacy_screen_lookup_exit(void) +{ +}

+#endif

On Mon, 06 Sep 2021, Hans de Goede hdegoede@redhat.com wrote:

Add X86 specific arch init code, which fills the privacy-screen lookup table by checking for various vendor specific ACPI interfaces for controlling the privacy-screen.

This initial version only checks for the Lenovo Thinkpad specific ACPI methods for privacy-screen control.

Reviewed-by: Emil Velikov emil.l.velikov@gmail.com Signed-off-by: Hans de Goede hdegoede@redhat.com

---

drivers/gpu/drm/Makefile | 2 +- drivers/gpu/drm/drm_privacy_screen_x86.c | 86 ++++++++++++++++++++++++ include/drm/drm_privacy_screen_machine.h | 5 ++ 3 files changed, 92 insertions(+), 1 deletion(-) create mode 100644 drivers/gpu/drm/drm_privacy_screen_x86.c

diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile index 788fc37096f6..12997ca5670d 100644 --- a/drivers/gpu/drm/Makefile +++ b/drivers/gpu/drm/Makefile @@ -32,7 +32,7 @@ drm-$(CONFIG_OF) += drm_of.o drm-$(CONFIG_PCI) += drm_pci.o drm-$(CONFIG_DEBUG_FS) += drm_debugfs.o drm_debugfs_crc.o drm-$(CONFIG_DRM_LOAD_EDID_FIRMWARE) += drm_edid_load.o -drm-$(CONFIG_DRM_PRIVACY_SCREEN) += drm_privacy_screen.o +drm-$(CONFIG_DRM_PRIVACY_SCREEN) += drm_privacy_screen.o drm_privacy_screen_x86.o

Would be nice to avoid building drm_privacy_screen_x86.o altogether for CONFIG_X86=n, and avoid...

obj-$(CONFIG_DRM_DP_AUX_BUS) += drm_dp_aux_bus.o

diff --git a/drivers/gpu/drm/drm_privacy_screen_x86.c b/drivers/gpu/drm/drm_privacy_screen_x86.c new file mode 100644 index 000000000000..a2cafb294ca6 --- /dev/null +++ b/drivers/gpu/drm/drm_privacy_screen_x86.c @@ -0,0 +1,86 @@ +// SPDX-License-Identifier: MIT +/*

• • Copyright (C) 2020 Red Hat, Inc.
• • Authors:
• • Hans de Goede hdegoede@redhat.com
• */

+#include <linux/acpi.h> +#include <drm/drm_privacy_screen_machine.h>

+#ifdef CONFIG_X86

...ifdefs that cover the entire file. This can be a future improvement, though.

+static struct drm_privacy_screen_lookup arch_lookup;

+struct arch_init_data {

• struct drm_privacy_screen_lookup lookup;
• bool (*detect)(void);

+};

+#if IS_ENABLED(CONFIG_THINKPAD_ACPI) +static acpi_status __init acpi_set_handle(acpi_handle handle, u32 level,

• 			  void *context, void **return_value)
  

+{

• *(acpi_handle *)return_value = handle;
• return AE_CTRL_TERMINATE;

+}

+static bool __init detect_thinkpad_privacy_screen(void) +{

• union acpi_object obj = { .type = ACPI_TYPE_INTEGER };
• struct acpi_object_list args = { .count = 1, .pointer = &obj, };
• acpi_handle ec_handle = NULL;
• unsigned long long output;
• acpi_status status;
• /* Get embedded-controller handle */
• status = acpi_get_devices("PNP0C09", acpi_set_handle, NULL, &ec_handle);
• if (ACPI_FAILURE(status) || !ec_handle)

• return false;
  

• /* And call the privacy-screen get-status method */
• status = acpi_evaluate_integer(ec_handle, "HKEY.GSSS", &args, &output);
• if (ACPI_FAILURE(status))

• return false;
  

• return (output & 0x10000) ? true : false;

+} +#endif

+static const struct arch_init_data arch_init_data[] __initconst = { +#if IS_ENABLED(CONFIG_THINKPAD_ACPI)

• {

• .lookup = {
  

• 	.dev_id = NULL,
  

• 	.con_id = NULL,
  

• 	.provider = "privacy_screen-thinkpad_acpi",
  

• },
  

• .detect = detect_thinkpad_privacy_screen,
  

• },

+#endif +};

+void __init drm_privacy_screen_lookup_init(void) +{

• int i;
• for (i = 0; i < ARRAY_SIZE(arch_init_data); i++) {

• if (!arch_init_data[i].detect())
  

• 	continue;
  

• pr_info("Found '%s' privacy-screen provider\n",
  

• 	arch_init_data[i].lookup.provider);
  

• /* Make a copy because arch_init_data is __initconst */
  

• arch_lookup = arch_init_data[i].lookup;
  

• drm_privacy_screen_lookup_add(&arch_lookup);
  

• break;
  

• }

+}

+void drm_privacy_screen_lookup_exit(void) +{

• if (arch_lookup.provider)

• drm_privacy_screen_lookup_remove(&arch_lookup);
  

+} +#endif /* ifdef CONFIG_X86 */ diff --git a/include/drm/drm_privacy_screen_machine.h b/include/drm/drm_privacy_screen_machine.h index aaa0d38cce92..02e5371904d3 100644 --- a/include/drm/drm_privacy_screen_machine.h +++ b/include/drm/drm_privacy_screen_machine.h @@ -31,11 +31,16 @@ struct drm_privacy_screen_lookup { void drm_privacy_screen_lookup_add(struct drm_privacy_screen_lookup *lookup); void drm_privacy_screen_lookup_remove(struct drm_privacy_screen_lookup *lookup);

+#if IS_ENABLED(CONFIG_DRM_PRIVACY_SCREEN) && IS_ENABLED(CONFIG_X86) +void drm_privacy_screen_lookup_init(void); +void drm_privacy_screen_lookup_exit(void); +#else static inline void drm_privacy_screen_lookup_init(void) { } static inline void drm_privacy_screen_lookup_exit(void) { } +#endif

#endif

Hi,

On 9/15/21 10:26 PM, Lyude Paul wrote:

On Mon, 2021-09-06 at 09:35 +0200, Hans de Goede wrote:

...

Add support for privacy-screen consumers to register a notifier to be notified of external (e.g. done by the hw itself on a hotkey press) state changes.

Reviewed-by: Emil Velikov emil.l.velikov@gmail.com Signed-off-by: Hans de Goede hdegoede@redhat.com

---

drivers/gpu/drm/drm_privacy_screen.c      | 67 +++++++++++++++++++++++  include/drm/drm_privacy_screen_consumer.h | 15 +++++  include/drm/drm_privacy_screen_driver.h   |  4 ++  3 files changed, 86 insertions(+)

diff --git a/drivers/gpu/drm/drm_privacy_screen.c b/drivers/gpu/drm/drm_privacy_screen.c index 294a09194bfb..7a5f878c3171 100644 --- a/drivers/gpu/drm/drm_privacy_screen.c +++ b/drivers/gpu/drm/drm_privacy_screen.c @@ -255,6 +255,49 @@ void drm_privacy_screen_get_state(struct drm_privacy_screen *priv,  }  EXPORT_SYMBOL(drm_privacy_screen_get_state);   +/**

• • drm_privacy_screen_register_notifier - register a notifier
• • @priv: Privacy screen to register the notifier with
• • @nb: Notifier-block for the notifier to register
• • Register a notifier with the privacy-screen to be notified of changes

made

• • to the privacy-screen state from outside of the privacy-screen class.
• • E.g. the state may be changed by the hardware itself in response to a
• • hotkey press.
• • The notifier is called with no locks held. The new hw_state and sw_state
• • can be retrieved using the drm_privacy_screen_get_state() function.
• • A pointer to the drm_privacy_screen's struct is passed as the void *data
• • argument of the notifier_block's notifier_call.
• • The notifier will NOT be called when changes are made through
• • drm_privacy_screen_set_sw_state(). It is only called for external

changes.

• • Return: 0 on success, negative error code on failure.
• */

+int drm_privacy_screen_register_notifier(struct drm_privacy_screen *priv, +                                        struct notifier_block *nb) +{ +       return blocking_notifier_chain_register(&priv->notifier_head, nb); +} +EXPORT_SYMBOL(drm_privacy_screen_register_notifier);

+/**

• • drm_privacy_screen_unregister_notifier - unregister a notifier
• • @priv: Privacy screen to register the notifier with
• • @nb: Notifier-block for the notifier to register
• • Unregister a notifier registered with

drm_privacy_screen_register_notifier().

• • Return: 0 on success, negative error code on failure.
• */

+int drm_privacy_screen_unregister_notifier(struct drm_privacy_screen *priv, +                                          struct notifier_block *nb) +{ +       return blocking_notifier_chain_unregister(&priv->notifier_head, nb); +} +EXPORT_SYMBOL(drm_privacy_screen_unregister_notifier);

/*** drm_privacy_screen_driver.h functions ***/    static ssize_t sw_state_show(struct device *dev, @@ -352,6 +395,7 @@ struct drm_privacy_screen *drm_privacy_screen_register(                 return ERR_PTR(-ENOMEM);           mutex_init(&priv->lock); +       BLOCKING_INIT_NOTIFIER_HEAD(&priv->notifier_head);           priv->dev.class = drm_class;         priv->dev.type = &drm_privacy_screen_type; @@ -399,3 +443,26 @@ void drm_privacy_screen_unregister(struct drm_privacy_screen *priv)         device_unregister(&priv->dev);  }  EXPORT_SYMBOL(drm_privacy_screen_unregister);

+/**

• • drm_privacy_screen_call_notifier_chain - notify consumers of state

change

• • @priv: Privacy screen to register the notifier with
• • A privacy-screen provider driver can call this functions upon external
• • changes to the privacy-screen state. E.g. the state may be changed by

the

• • hardware itself in response to a hotkey press.
• • This function must be called without holding the privacy-screen lock.
• • the driver must update sw_state and hw_state to reflect the new state

before

• • calling this function.
• • The expected behavior from the driver upon receiving an external state
• • change event is: 1. Take the lock; 2. Update sw_state and hw_state;
• • 3. Release the lock. 4. Call drm_privacy_screen_call_notifier_chain().
• */

+void drm_privacy_screen_call_notifier_chain(struct drm_privacy_screen *priv) +{ +       if (WARN_ON(mutex_is_locked(&priv->lock))) +               return;

Are we sure about this check? mutex_is_locked() checks whether a mutex is locked by anyone, not just us. So this seems like it would cause us to WARN_ON() and abort if anyone else (not just ourselves) is holding the lock to read the privacy screen state.

Thank you for catching this, yes this check indeed is wrong. AFAIK there is no way to check that the mutex has been locked by us, so this extra sanity check simply needs to be removed.

I'll drop the check before pushing this to drm-misc-next (more on that in a reply to the cover letter), if that is ok with you.

Or do you want me to do a new version addressing this?

Regards,

Hans

...

+       blocking_notifier_call_chain(&priv->notifier_head, 0, priv); +} +EXPORT_SYMBOL(drm_privacy_screen_call_notifier_chain); diff --git a/include/drm/drm_privacy_screen_consumer.h b/include/drm/drm_privacy_screen_consumer.h index 0cbd23b0453d..7f66a90d15b7 100644 --- a/include/drm/drm_privacy_screen_consumer.h +++ b/include/drm/drm_privacy_screen_consumer.h @@ -24,6 +24,11 @@ int drm_privacy_screen_set_sw_state(struct drm_privacy_screen *priv,  void drm_privacy_screen_get_state(struct drm_privacy_screen *priv,                                   enum drm_privacy_screen_status *sw_state_ret,                                   enum drm_privacy_screen_status *hw_state_ret);

+int drm_privacy_screen_register_notifier(struct drm_privacy_screen *priv, +                                        struct notifier_block *nb); +int drm_privacy_screen_unregister_notifier(struct drm_privacy_screen *priv, +                                          struct notifier_block *nb);  #else  static inline struct drm_privacy_screen *drm_privacy_screen_get(struct device *dev,                                                                 const char *con_id) @@ -45,6 +50,16 @@ static inline void drm_privacy_screen_get_state(struct drm_privacy_screen *priv,         *sw_state_ret = PRIVACY_SCREEN_DISABLED;         *hw_state_ret = PRIVACY_SCREEN_DISABLED;  } +static inline int drm_privacy_screen_register_notifier(struct drm_privacy_screen *priv, +                                                      struct notifier_block *nb) +{ +       return -ENODEV; +} +static inline int drm_privacy_screen_unregister_notifier(struct drm_privacy_screen *priv, +                                                        struct notifier_block *nb) +{ +       return -ENODEV; +}  #endif    #endif diff --git a/include/drm/drm_privacy_screen_driver.h b/include/drm/drm_privacy_screen_driver.h index 5187ae52eb03..24591b607675 100644 --- a/include/drm/drm_privacy_screen_driver.h +++ b/include/drm/drm_privacy_screen_driver.h @@ -54,6 +54,8 @@ struct drm_privacy_screen {         struct mutex lock;         /** @list: privacy-screen devices list list-entry. */         struct list_head list; +       /** @notifier_head: privacy-screen notifier head. */ +       struct blocking_notifier_head notifier_head;         /**          * @ops: &struct drm_privacy_screen_ops for this privacy-screen.          * This is NULL if the driver has unregistered the privacy-screen. @@ -77,4 +79,6 @@ struct drm_privacy_screen *drm_privacy_screen_register(         struct device *parent, const struct drm_privacy_screen_ops *ops);  void drm_privacy_screen_unregister(struct drm_privacy_screen *priv);   +void drm_privacy_screen_call_notifier_chain(struct drm_privacy_screen *priv);

#endif

On Mon, 2021-09-06 at 09:35 +0200, Hans de Goede wrote:

Register a privacy-screen device on laptops with a privacy-screen, this exports the PrivacyGuard features to user-space using a standardized vendor-agnostic sysfs interface. Note the sysfs interface is read-only.

Registering a privacy-screen device with the new privacy-screen class code will also allow the GPU driver to get a handle to it and export the privacy-screen setting as a property on the DRM connector object for the LCD panel. This DRM connector property is news standardized

Looks like a typo here ------------------------------^

interface which all user-space code should use to query and control the privacy-screen.

Reviewed-by: Emil Velikov emil.l.velikov@gmail.com Signed-off-by: Hans de Goede hdegoede@redhat.com

---

Changes in v2:

• Make the new lcdshadow_set_sw_state, lcdshadow_get_hw_state and

lcdshadow_ops symbols static

• Update state and call drm_privacy_screen_call_notifier_chain()

when the state is changed by pressing the Fn + D hotkey combo

drivers/platform/x86/Kconfig         |  2 +  drivers/platform/x86/thinkpad_acpi.c | 91 ++++++++++++++++++++--------  2 files changed, 68 insertions(+), 25 deletions(-)

diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig index d12db6c316ea..ae00a27f9f95 100644 --- a/drivers/platform/x86/Kconfig +++ b/drivers/platform/x86/Kconfig @@ -509,7 +509,9 @@ config THINKPAD_ACPI         depends on ACPI_VIDEO || ACPI_VIDEO = n         depends on BACKLIGHT_CLASS_DEVICE         depends on I2C +       depends on DRM         select ACPI_PLATFORM_PROFILE +       select DRM_PRIVACY_SCREEN         select HWMON         select NVRAM         select NEW_LEDS diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c index b8f2556c4797..044b238730ba 100644 --- a/drivers/platform/x86/thinkpad_acpi.c +++ b/drivers/platform/x86/thinkpad_acpi.c @@ -73,6 +73,7 @@  #include <linux/uaccess.h>  #include <acpi/battery.h>  #include <acpi/video.h> +#include <drm/drm_privacy_screen_driver.h>  #include "dual_accel_detect.h"    /* ThinkPad CMOS commands */ @@ -157,6 +158,7 @@ enum tpacpi_hkey_event_t {         TP_HKEY_EV_VOL_UP               = 0x1015, /* Volume up or unmute */         TP_HKEY_EV_VOL_DOWN             = 0x1016, /* Volume down or unmute */         TP_HKEY_EV_VOL_MUTE             = 0x1017, /* Mixer output mute */ +       TP_HKEY_EV_PRIVACYGUARD_TOGGLE  = 0x130f, /* Toggle priv.guard on/off */           /* Reasons for waking up from S3/S4 */         TP_HKEY_EV_WKUP_S3_UNDOCK       = 0x2304, /* undock requested, S3 */ @@ -3889,6 +3891,12 @@ static bool hotkey_notify_extended_hotkey(const u32 hkey)  {         unsigned int scancode;   +       switch (hkey) { +       case TP_HKEY_EV_PRIVACYGUARD_TOGGLE: +               tpacpi_driver_event(hkey); +               return true; +       }

/* Extended keycodes start at 0x300 and our offset into the map          * TP_ACPI_HOTKEYSCAN_EXTENDED_START. The calculated scancode          * will be positive, but might not be in the correct range. @@ -9819,30 +9827,40 @@ static struct ibm_struct battery_driver_data = {   * LCD Shadow subdriver, for the Lenovo PrivacyGuard feature   */   +static struct drm_privacy_screen *lcdshadow_dev;  static acpi_handle lcdshadow_get_handle;  static acpi_handle lcdshadow_set_handle; -static int lcdshadow_state;   -static int lcdshadow_on_off(bool state) +static int lcdshadow_set_sw_state(struct drm_privacy_screen *priv, +                                 enum drm_privacy_screen_status state)  {         int output;   +       if (WARN_ON(!mutex_is_locked(&priv->lock))) +               return -EIO;

if (!acpi_evalf(lcdshadow_set_handle, &output, NULL, "dd", (int)state))                 return -EIO;   -       lcdshadow_state = state; +       priv->hw_state = priv->sw_state = state;         return 0;  }   -static int lcdshadow_set(bool on) +static void lcdshadow_get_hw_state(struct drm_privacy_screen *priv)  { -       if (lcdshadow_state < 0) -               return lcdshadow_state; -       if (lcdshadow_state == on) -               return 0; -       return lcdshadow_on_off(on); +       int output;

+       if (!acpi_evalf(lcdshadow_get_handle, &output, NULL, "dd", 0)) +               return;

+       priv->hw_state = priv->sw_state = output & 0x1;  }   +static const struct drm_privacy_screen_ops lcdshadow_ops = { +       .set_sw_state = lcdshadow_set_sw_state, +       .get_hw_state = lcdshadow_get_hw_state, +};

static int tpacpi_lcdshadow_init(struct ibm_init_struct *iibm)  {         acpi_status status1, status2; @@ -9850,36 +9868,44 @@ static int tpacpi_lcdshadow_init(struct ibm_init_struct *iibm)           status1 = acpi_get_handle(hkey_handle, "GSSS", &lcdshadow_get_handle);         status2 = acpi_get_handle(hkey_handle, "SSSS", &lcdshadow_set_handle); -       if (ACPI_FAILURE(status1) || ACPI_FAILURE(status2)) { -               lcdshadow_state = -ENODEV; +       if (ACPI_FAILURE(status1) || ACPI_FAILURE(status2))                 return 0; -       }   -       if (!acpi_evalf(lcdshadow_get_handle, &output, NULL, "dd", 0)) { -               lcdshadow_state = -EIO; +       if (!acpi_evalf(lcdshadow_get_handle, &output, NULL, "dd", 0))                 return -EIO; -       } -       if (!(output & 0x10000)) { -               lcdshadow_state = -ENODEV;

+       if (!(output & 0x10000))                 return 0; -       } -       lcdshadow_state = output & 0x1;

+       lcdshadow_dev = drm_privacy_screen_register(&tpacpi_pdev->dev, +                                                   &lcdshadow_ops); +       if (IS_ERR(lcdshadow_dev)) +               return PTR_ERR(lcdshadow_dev);           return 0;  }   +static void lcdshadow_exit(void) +{ +       drm_privacy_screen_unregister(lcdshadow_dev); +}

static void lcdshadow_resume(void)  { -       if (lcdshadow_state >= 0) -               lcdshadow_on_off(lcdshadow_state); +       if (!lcdshadow_dev) +               return;

+       mutex_lock(&lcdshadow_dev->lock); +       lcdshadow_set_sw_state(lcdshadow_dev, lcdshadow_dev->sw_state); +       mutex_unlock(&lcdshadow_dev->lock);  }

For privacy screens provided by x86 platform drivers this is -probably- correct, but only so long as we're confident that the privacy screen is always going to be controllable regardless of the power state of the actual LCD panel.

I'd think we would need to handle suspend/resume in the atomic commit though if we ever have to support systems where the two are dependent on one another, but, that's a simple enough change to do later if it arises that I think we can ignore it for now.

static int lcdshadow_read(struct seq_file *m)  { -       if (lcdshadow_state < 0) { +       if (!lcdshadow_dev) {                 seq_puts(m, "status:\t\tnot supported\n");         } else { -               seq_printf(m, "status:\t\t%d\n", lcdshadow_state); +               seq_printf(m, "status:\t\t%d\n", lcdshadow_dev->hw_state);                 seq_puts(m, "commands:\t0, 1\n");         }   @@ -9891,7 +9917,7 @@ static int lcdshadow_write(char *buf)         char *cmd;         int res, state = -EINVAL;   -       if (lcdshadow_state < 0) +       if (!lcdshadow_dev)                 return -ENODEV;           while ((cmd = strsep(&buf, ","))) { @@ -9903,11 +9929,18 @@ static int lcdshadow_write(char *buf)         if (state >= 2 || state < 0)                 return -EINVAL;   -       return lcdshadow_set(state); +       mutex_lock(&lcdshadow_dev->lock); +       res = lcdshadow_set_sw_state(lcdshadow_dev, state); +       mutex_unlock(&lcdshadow_dev->lock);

+       drm_privacy_screen_call_notifier_chain(lcdshadow_dev);

+       return res;  }    static struct ibm_struct lcdshadow_driver_data = {         .name = "lcdshadow", +       .exit = lcdshadow_exit,         .resume = lcdshadow_resume,         .read = lcdshadow_read,         .write = lcdshadow_write, @@ -10717,6 +10750,14 @@ static void tpacpi_driver_event(const unsigned int hkey_event)                 if (!atomic_add_unless(&dytc_ignore_event, -1, 0))                         dytc_profile_refresh();         }

+       if (lcdshadow_dev && hkey_event == TP_HKEY_EV_PRIVACYGUARD_TOGGLE) { +               mutex_lock(&lcdshadow_dev->lock); +               lcdshadow_get_hw_state(lcdshadow_dev); +               mutex_unlock(&lcdshadow_dev->lock);

+               drm_privacy_screen_call_notifier_chain(lcdshadow_dev); +       }  }    static void hotkey_driver_event(const unsigned int scancode)

Hi,

On 9/15/21 11:11 PM, Lyude Paul wrote:

On Mon, 2021-09-06 at 09:35 +0200, Hans de Goede wrote:

...

Add support for eDP panels with a built-in privacy screen using the new drm_privacy_screen class.

One thing which stands out here is the addition of these 2 lines to intel_atomic_commit_tail:

for_each_new_connector_in_state(&state->base, connector, ...                 drm_connector_update_privacy_screen(connector, state);

It may seem more logical to instead take care of updating the privacy-screen state by marking the crtc as needing a modeset and then do this in both the encoder update_pipe (for fast-sets) and enable (for full modesets) callbacks. But ATM these callbacks only get passed the new connector_state and these callbacks are all called after drm_atomic_helper_swap_state() at which point there is no way to get the old state from the new state.

I was going to suggest that you workaround this simply by adding a variable that corresponds to the most recently committed privacy screen state somewhere in a driver private structure. But, then I realized that's basically the same as what you're doing now except that your current solution stores said state in a shared struct. So, I think you probably do have the right idea here as long as we don't get any non-ACPI providers in the future. This also seems like something that wouldn't be difficult to fixup down the line if that ends up changing.

Ack, this is all kernel internal stuff so we can always rework it if necessary.

Regards,

Hans

...

Without access to the old state, we do not know if the sw_state of the privacy-screen has changes so we would need to call drm_privacy_screen_set_sw_state() unconditionally. This is undesirable since all current known privacy-screen providers use ACPI calls which are somewhat expensive to make.

Also, as all providers use ACPI calls, rather then poking GPU registers, there is no need to order this together with other encoder operations. Since no GPU poking is involved having this as a separate step of the commit process actually is the logical thing to do.

Reviewed-by: Emil Velikov emil.l.velikov@gmail.com Signed-off-by: Hans de Goede hdegoede@redhat.com

---

drivers/gpu/drm/i915/display/intel_display.c |  5 +++++  drivers/gpu/drm/i915/display/intel_dp.c      | 10 ++++++++++  drivers/gpu/drm/i915/i915_pci.c              | 12 ++++++++++++  3 files changed, 27 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c index 5560d2f4c352..7285873d329a 100644 --- a/drivers/gpu/drm/i915/display/intel_display.c +++ b/drivers/gpu/drm/i915/display/intel_display.c @@ -10140,6 +10140,8 @@ static void intel_atomic_commit_tail(struct intel_atomic_state *state)         struct drm_device *dev = state->base.dev;         struct drm_i915_private *dev_priv = to_i915(dev);         struct intel_crtc_state *new_crtc_state, *old_crtc_state; +       struct drm_connector_state *new_connector_state; +       struct drm_connector *connector;         struct intel_crtc *crtc;         u64 put_domains[I915_MAX_PIPES] = {};         intel_wakeref_t wakeref = 0; @@ -10237,6 +10239,9 @@ static void intel_atomic_commit_tail(struct intel_atomic_state *state)                         intel_color_load_luts(new_crtc_state);         }   +       for_each_new_connector_in_state(&state->base, connector, new_connector_state, i) +               drm_connector_update_privacy_screen(connector, &state-

...

base);

/*          * Now that the vblank has passed, we can go ahead and program the          * optimal watermarks on platforms that need two-step watermark diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c index 7f8e8865048f..3aa2072cccf6 100644 --- a/drivers/gpu/drm/i915/display/intel_dp.c +++ b/drivers/gpu/drm/i915/display/intel_dp.c @@ -37,6 +37,7 @@  #include <drm/drm_crtc.h>  #include <drm/drm_dp_helper.h>  #include <drm/drm_edid.h> +#include <drm/drm_privacy_screen_consumer.h>  #include <drm/drm_probe_helper.h>    #include "g4x_dp.h" @@ -5217,6 +5218,7 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp,         struct drm_connector *connector = &intel_connector->base;         struct drm_display_mode *fixed_mode = NULL;         struct drm_display_mode *downclock_mode = NULL; +       struct drm_privacy_screen *privacy_screen;         bool has_dpcd;         enum pipe pipe = INVALID_PIPE;         struct edid *edid; @@ -5308,6 +5310,14 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp,                                 fixed_mode->hdisplay, fixed_mode->vdisplay);         }   +       privacy_screen = drm_privacy_screen_get(dev->dev, NULL); +       if (!IS_ERR(privacy_screen)) { +               drm_connector_attach_privacy_screen_provider(connector, +                                                            privacy_screen); +       } else if (PTR_ERR(privacy_screen) != -ENODEV) { +               drm_warn(&dev_priv->drm, "Error getting privacy-screen\n"); +       }

return true;    out_vdd_off: diff --git a/drivers/gpu/drm/i915/i915_pci.c b/drivers/gpu/drm/i915/i915_pci.c index 146f7e39182a..d6913f567a1c 100644 --- a/drivers/gpu/drm/i915/i915_pci.c +++ b/drivers/gpu/drm/i915/i915_pci.c @@ -25,6 +25,7 @@  #include <linux/vga_switcheroo.h>    #include <drm/drm_drv.h> +#include <drm/drm_privacy_screen_consumer.h>  #include <drm/i915_pciids.h>    #include "i915_drv.h" @@ -1167,6 +1168,7 @@ static int i915_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)  {         struct intel_device_info *intel_info =                 (struct intel_device_info *) ent->driver_data; +       struct drm_privacy_screen *privacy_screen;         int err;           if (intel_info->require_force_probe && @@ -1195,7 +1197,17 @@ static int i915_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)         if (vga_switcheroo_client_probe_defer(pdev))                 return -EPROBE_DEFER;   +       /* +        * We do not handle -EPROBE_DEFER further into the probe process, so +        * check if we have a laptop-panel privacy-screen for which the driver +        * has not loaded yet here. +        */ +       privacy_screen = drm_privacy_screen_get(&pdev->dev, NULL); +       if (IS_ERR(privacy_screen) && PTR_ERR(privacy_screen) == - EPROBE_DEFER) +               return -EPROBE_DEFER;

err = i915_driver_probe(pdev, ent); +       drm_privacy_screen_put(privacy_screen);         if (err)                 return err;

Hi,

On 9/16/21 11:40 AM, Jani Nikula wrote:

Cc: Ville for input here, see question inline.

On Mon, 06 Sep 2021, Hans de Goede hdegoede@redhat.com wrote:

...

Add support for eDP panels with a built-in privacy screen using the new drm_privacy_screen class.

One thing which stands out here is the addition of these 2 lines to intel_atomic_commit_tail:

for_each_new_connector_in_state(&state->base, connector, ... drm_connector_update_privacy_screen(connector, state);

It may seem more logical to instead take care of updating the privacy-screen state by marking the crtc as needing a modeset and then do this in both the encoder update_pipe (for fast-sets) and enable (for full modesets) callbacks. But ATM these callbacks only get passed the new connector_state and these callbacks are all called after drm_atomic_helper_swap_state() at which point there is no way to get the old state from the new state.

Without access to the old state, we do not know if the sw_state of the privacy-screen has changes so we would need to call drm_privacy_screen_set_sw_state() unconditionally. This is undesirable since all current known privacy-screen providers use ACPI calls which are somewhat expensive to make.

Also, as all providers use ACPI calls, rather then poking GPU registers, there is no need to order this together with other encoder operations. Since no GPU poking is involved having this as a separate step of the commit process actually is the logical thing to do.

Reviewed-by: Emil Velikov emil.l.velikov@gmail.com Signed-off-by: Hans de Goede hdegoede@redhat.com

---

drivers/gpu/drm/i915/display/intel_display.c | 5 +++++ drivers/gpu/drm/i915/display/intel_dp.c | 10 ++++++++++ drivers/gpu/drm/i915/i915_pci.c | 12 ++++++++++++ 3 files changed, 27 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c index 5560d2f4c352..7285873d329a 100644 --- a/drivers/gpu/drm/i915/display/intel_display.c +++ b/drivers/gpu/drm/i915/display/intel_display.c @@ -10140,6 +10140,8 @@ static void intel_atomic_commit_tail(struct intel_atomic_state *state) struct drm_device *dev = state->base.dev; struct drm_i915_private *dev_priv = to_i915(dev); struct intel_crtc_state *new_crtc_state, *old_crtc_state;

• struct drm_connector_state *new_connector_state;
• struct drm_connector *connector; struct intel_crtc *crtc; u64 put_domains[I915_MAX_PIPES] = {}; intel_wakeref_t wakeref = 0;

@@ -10237,6 +10239,9 @@ static void intel_atomic_commit_tail(struct intel_atomic_state *state) intel_color_load_luts(new_crtc_state); }

• for_each_new_connector_in_state(&state->base, connector, new_connector_state, i)

• drm_connector_update_privacy_screen(connector, &state->base);
  

• /*
  • Now that the vblank has passed, we can go ahead and program the
  • optimal watermarks on platforms that need two-step watermark

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c index 7f8e8865048f..3aa2072cccf6 100644 --- a/drivers/gpu/drm/i915/display/intel_dp.c +++ b/drivers/gpu/drm/i915/display/intel_dp.c @@ -37,6 +37,7 @@ #include <drm/drm_crtc.h> #include <drm/drm_dp_helper.h> #include <drm/drm_edid.h> +#include <drm/drm_privacy_screen_consumer.h> #include <drm/drm_probe_helper.h>

#include "g4x_dp.h" @@ -5217,6 +5218,7 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp, struct drm_connector *connector = &intel_connector->base; struct drm_display_mode *fixed_mode = NULL; struct drm_display_mode *downclock_mode = NULL;

• struct drm_privacy_screen *privacy_screen; bool has_dpcd; enum pipe pipe = INVALID_PIPE; struct edid *edid;

@@ -5308,6 +5310,14 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp, fixed_mode->hdisplay, fixed_mode->vdisplay); }

• privacy_screen = drm_privacy_screen_get(dev->dev, NULL);
• if (!IS_ERR(privacy_screen)) {

• drm_connector_attach_privacy_screen_provider(connector,
  

• 					     privacy_screen);
  

• } else if (PTR_ERR(privacy_screen) != -ENODEV) {

• drm_warn(&dev_priv->drm, "Error getting privacy-screen\n");
  

• }
• return true;

out_vdd_off: diff --git a/drivers/gpu/drm/i915/i915_pci.c b/drivers/gpu/drm/i915/i915_pci.c index 146f7e39182a..d6913f567a1c 100644 --- a/drivers/gpu/drm/i915/i915_pci.c +++ b/drivers/gpu/drm/i915/i915_pci.c @@ -25,6 +25,7 @@ #include <linux/vga_switcheroo.h>

#include <drm/drm_drv.h> +#include <drm/drm_privacy_screen_consumer.h> #include <drm/i915_pciids.h>

#include "i915_drv.h" @@ -1167,6 +1168,7 @@ static int i915_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent) { struct intel_device_info *intel_info = (struct intel_device_info *) ent->driver_data;

• struct drm_privacy_screen *privacy_screen; int err;

  if (intel_info->require_force_probe &&

@@ -1195,7 +1197,17 @@ static int i915_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent) if (vga_switcheroo_client_probe_defer(pdev)) return -EPROBE_DEFER;

• /*

• * We do not handle -EPROBE_DEFER further into the probe process, so
  

• * check if we have a laptop-panel privacy-screen for which the driver
  

• * has not loaded yet here.
  

• */
  

• privacy_screen = drm_privacy_screen_get(&pdev->dev, NULL);
• if (IS_ERR(privacy_screen) && PTR_ERR(privacy_screen) == -EPROBE_DEFER)

• return -EPROBE_DEFER;
  

• err = i915_driver_probe(pdev, ent);
• drm_privacy_screen_put(privacy_screen); if (err) return err;

Ideally, neither i915_pci_probe() nor i915_driver_probe() should assume we have display. We might not. We should not wait if we are never going to initialize display.

Good point.

Alas, we'll only know after i915_driver_probe() -> i915_driver_mmio_probe() -> intel_device_info_runtime_init(), which modifies ->pipe_mask, which is the single point of truth. See HAS_DISPLAY().

We do have tests for failing probe at various points (see the i915_inject_probe_failure() calls) to stress the cleanup paths in CI. Part of the point was to prepare us for -EPROBE_DEFER returns.

Looks like the earliest/cleanest point for checking this is in intel_modeset_init_noirq(), i.e. first display init call. But I admit it gives me an uneasy feeling to return -EPROBE_DEFER at that stage.

Ack, this is why I added the get + put here. Theoretically I could also just have put the return -EPROBE_DEFER inside intel_edp_init_connector() (changing its return type) but I did not feel comfortable with doing that...

I think that just leaving this functionally as is, with the refactor which you suggest below is best for now. drm_privacy_screen_get() will only return -EPROBE_DEFER if there is an entry in the lookup-table which the drm_privacy class code keeps this lookup table matches on the dev_name() of the GPU's PCI-device. So assuming the lookup table contains the correct dev_name() then there should be no match for any GPU-s without a display.

Note ATM this is not true since the lookup added for the thinkpad_acpi providing privacy-screen support case specifies NULL as dev_name, which gets interpreted as a wildcard, but I can easily replace that with "0000:00:02.0" before pushing this out. Which at least avoids delaying probing of any discrete Intel GPUs which I guess may not have displays.

That does still leave the case of a hybrid GPU laptop where all displays are connected to the discrete-GPU and the iGPU is only left enabled for quick-sync functionality. But I'm not sure if that case is even detected by HAS_DISPLAY(), since the hw then still has display-pipes.

Worst case scenario here is that we delay i915 binding to the device until thinkpad_acpi loads, which I think is not too bad.

Note a downside of replace the NULL devname in the lookup with "0000:00:02.0" is that that will not work for hybrid-gfx laptops with the panel connected to the discrete-GPU atm this is not supported anyways since amdgpu and nouveau lack a patch similar to this one.

But the plan was for this to work automatically as soon as nouveau / amdgpu get support assuming that e.g. only either i915 or nouveau would see the LCD panel and thus would trigger the code in e.g. intel_edp_init_connector().

But if you feel more comfortable about this if I change the dev_name in the lookup to "0000:00:02.0" I can do that and we can cross the hybrid-gfx case when we hit that. The whole need to tie a random vendor ACPI interface for privacy-screen control together with the drm-subsys is a bit messy anyways, so some of this we (I?) will need to figure out as we go.

The only -EPROBE_DEFER return we currently have is the vga switcheroo stuff you see in the patch context, and most platforms never return that.

Ville, I'd like to get your thoughts on that.

Anyway, even if we decide not to, err, defer returning -EPROBE_DEFER, I think we should abstract this better. For example, add a intel_modeset_probe_defer() function in intel_display.c that checks this, and call that as the first thing in i915_driver_probe(). Just to keep the display specific code out of the high level functions, even if that is functionally the same as what you're doing here.

I'm fine with refactoring this a bit and adding an intel_modeset_probe_defer() helper for this, I assume I should also move the vga_switcheroo_client_probe_defer(pdev) check there?

As you suggested yourself in your reply to the coverletter I will push out the rest of the series to drm-misc-next while we figure this out. Assuming Lyude is happy with the answers which I gave to her remarks about some of the other patches.

Regards,

Hans

On Thu, Sep 16, 2021 at 12:40:11PM +0300, Jani Nikula wrote:

Cc: Ville for input here, see question inline.

On Mon, 06 Sep 2021, Hans de Goede hdegoede@redhat.com wrote:

...

Add support for eDP panels with a built-in privacy screen using the new drm_privacy_screen class.

One thing which stands out here is the addition of these 2 lines to intel_atomic_commit_tail:

for_each_new_connector_in_state(&state->base, connector, ... drm_connector_update_privacy_screen(connector, state);

It may seem more logical to instead take care of updating the privacy-screen state by marking the crtc as needing a modeset and then do this in both the encoder update_pipe (for fast-sets) and enable (for full modesets) callbacks. But ATM these callbacks only get passed the new connector_state and these callbacks are all called after drm_atomic_helper_swap_state() at which point there is no way to get the old state from the new state.

Without access to the old state, we do not know if the sw_state of the privacy-screen has changes so we would need to call drm_privacy_screen_set_sw_state() unconditionally. This is undesirable since all current known privacy-screen providers use ACPI calls which are somewhat expensive to make.

Also, as all providers use ACPI calls, rather then poking GPU registers, there is no need to order this together with other encoder operations. Since no GPU poking is involved having this as a separate step of the commit process actually is the logical thing to do.

Reviewed-by: Emil Velikov emil.l.velikov@gmail.com Signed-off-by: Hans de Goede hdegoede@redhat.com

---

drivers/gpu/drm/i915/display/intel_display.c | 5 +++++ drivers/gpu/drm/i915/display/intel_dp.c | 10 ++++++++++ drivers/gpu/drm/i915/i915_pci.c | 12 ++++++++++++ 3 files changed, 27 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c index 5560d2f4c352..7285873d329a 100644 --- a/drivers/gpu/drm/i915/display/intel_display.c +++ b/drivers/gpu/drm/i915/display/intel_display.c @@ -10140,6 +10140,8 @@ static void intel_atomic_commit_tail(struct intel_atomic_state *state) struct drm_device *dev = state->base.dev; struct drm_i915_private *dev_priv = to_i915(dev); struct intel_crtc_state *new_crtc_state, *old_crtc_state;

• struct drm_connector_state *new_connector_state;
• struct drm_connector *connector; struct intel_crtc *crtc; u64 put_domains[I915_MAX_PIPES] = {}; intel_wakeref_t wakeref = 0;

@@ -10237,6 +10239,9 @@ static void intel_atomic_commit_tail(struct intel_atomic_state *state) intel_color_load_luts(new_crtc_state); }

• for_each_new_connector_in_state(&state->base, connector, new_connector_state, i)

• drm_connector_update_privacy_screen(connector, &state->base);
  

• /*
  • Now that the vblank has passed, we can go ahead and program the
  • optimal watermarks on platforms that need two-step watermark

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c index 7f8e8865048f..3aa2072cccf6 100644 --- a/drivers/gpu/drm/i915/display/intel_dp.c +++ b/drivers/gpu/drm/i915/display/intel_dp.c @@ -37,6 +37,7 @@ #include <drm/drm_crtc.h> #include <drm/drm_dp_helper.h> #include <drm/drm_edid.h> +#include <drm/drm_privacy_screen_consumer.h> #include <drm/drm_probe_helper.h>

#include "g4x_dp.h" @@ -5217,6 +5218,7 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp, struct drm_connector *connector = &intel_connector->base; struct drm_display_mode *fixed_mode = NULL; struct drm_display_mode *downclock_mode = NULL;

• struct drm_privacy_screen *privacy_screen; bool has_dpcd; enum pipe pipe = INVALID_PIPE; struct edid *edid;

@@ -5308,6 +5310,14 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp, fixed_mode->hdisplay, fixed_mode->vdisplay); }

• privacy_screen = drm_privacy_screen_get(dev->dev, NULL);
• if (!IS_ERR(privacy_screen)) {

• drm_connector_attach_privacy_screen_provider(connector,
  

• 					     privacy_screen);
  

• } else if (PTR_ERR(privacy_screen) != -ENODEV) {

• drm_warn(&dev_priv->drm, "Error getting privacy-screen\n");
  

• }
• return true;

out_vdd_off: diff --git a/drivers/gpu/drm/i915/i915_pci.c b/drivers/gpu/drm/i915/i915_pci.c index 146f7e39182a..d6913f567a1c 100644 --- a/drivers/gpu/drm/i915/i915_pci.c +++ b/drivers/gpu/drm/i915/i915_pci.c @@ -25,6 +25,7 @@ #include <linux/vga_switcheroo.h>

#include <drm/drm_drv.h> +#include <drm/drm_privacy_screen_consumer.h> #include <drm/i915_pciids.h>

#include "i915_drv.h" @@ -1167,6 +1168,7 @@ static int i915_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent) { struct intel_device_info *intel_info = (struct intel_device_info *) ent->driver_data;

• struct drm_privacy_screen *privacy_screen; int err;

  if (intel_info->require_force_probe &&

@@ -1195,7 +1197,17 @@ static int i915_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent) if (vga_switcheroo_client_probe_defer(pdev)) return -EPROBE_DEFER;

• /*

• * We do not handle -EPROBE_DEFER further into the probe process, so
  

• * check if we have a laptop-panel privacy-screen for which the driver
  

• * has not loaded yet here.
  

• */
  

• privacy_screen = drm_privacy_screen_get(&pdev->dev, NULL);
• if (IS_ERR(privacy_screen) && PTR_ERR(privacy_screen) == -EPROBE_DEFER)

• return -EPROBE_DEFER;
  

• err = i915_driver_probe(pdev, ent);
• drm_privacy_screen_put(privacy_screen); if (err) return err;

Ideally, neither i915_pci_probe() nor i915_driver_probe() should assume we have display. We might not. We should not wait if we are never going to initialize display.

Alas, we'll only know after i915_driver_probe() -> i915_driver_mmio_probe() -> intel_device_info_runtime_init(), which modifies ->pipe_mask, which is the single point of truth. See HAS_DISPLAY().

We do have tests for failing probe at various points (see the i915_inject_probe_failure() calls) to stress the cleanup paths in CI. Part of the point was to prepare us for -EPROBE_DEFER returns.

Looks like the earliest/cleanest point for checking this is in intel_modeset_init_noirq(), i.e. first display init call. But I admit it gives me an uneasy feeling to return -EPROBE_DEFER at that stage. The only -EPROBE_DEFER return we currently have is the vga switcheroo stuff you see in the patch context, and most platforms never return that.

Ville, I'd like to get your thoughts on that.

I'm just scaread about everything to do with deferred probing.

For example, I don't even know what would happen if you have some kind of mismatch betwen i915 and thinkpad_acpi y/m/n? Or you have one but not the other in the initrd? Is the machine at least guaranteed to boot properly and light up the display at some point?

But yeah, failing the probe at some stage when we've already clobbered a bunch of things sounds like an "interesting" idea. I don't think we've given the error paths any real though beyond the "ci+error injection seems to not explode too badly" approach.

Anyway, even if we decide not to, err, defer returning -EPROBE_DEFER, I think we should abstract this better. For example, add a intel_modeset_probe_defer() function in intel_display.c that checks this, and call that as the first thing in i915_driver_probe(). Just to keep the display specific code out of the high level functions, even if that is functionally the same as what you're doing here.

Yeah, I guess something like that could be the safest option for the moment.