[PATCH RFC v3] drm: Add a new connector atomic property for link status
Manasi Navare
manasi.d.navare at intel.com
Tue Nov 29 01:07:52 UTC 2016
On Thu, Nov 24, 2016 at 08:51:35AM +0100, Daniel Vetter wrote:
> On Wed, Nov 23, 2016 at 11:28:21PM -0800, Manasi Navare wrote:
> > This is RFC patch for adding a connector link-status property
> > and making it atomic by adding it to the drm_connector_state.
> > This is to make sure its wired properly in drm_atomic_connector_set_property
> > and drm_atomic_connector_get_property functions.
> >
> > v3:
> > * Fixed a build error (Jani Saarinen)
> > v2:
> > * Removed connector->link_status (Daniel Vetter)
> > * Set connector->state->link_status in drm_mode_connector_set_link_status_property
> > (Daniel Vetter)
> > * Set the connector_changed flag to true if connector->state->link_status changed.
> > * Reset link_status to GOOD in update_output_state (Daniel Vetter)
> > * Never allow userspace to set link status from Good To Bad (Daniel Vetter)
> >
> > Cc: Jani Nikula <jani.nikula at linux.intel.com>
> > Cc: Daniel Vetter <daniel.vetter at intel.com>
> > Cc: Ville Syrjala <ville.syrjala at linux.intel.com>
> > Cc: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: Sean Paul <seanpaul at chromium.org>
>
> You lost all the acked-by from AMD about the link-status property. We need
> those.
>
> > Signed-off-by: Manasi Navare <manasi.d.navare at intel.com>
>
> Yeah I think this should work, but obviously testing has the final say.
> Some nitpicks below, then it's r-b: me. But I think we also need to polish
> the kernel-doc a bit more to address Sean Paul's questions.
> -Daniel
>
I tested it with SNA driver with Chris's changes to read the link-status
property, but It is not able to detect the link-status property being set to BAD
and hence it does not trigger a new modeset.
Do we need to make any changes to the SNA driver now that this is made a ATOMIC
property so that GETCONNECTOR IOCTL can still read the correct value
of this property throught drm_atomic_get_property() interface?
Chris, Daniel, any thoughts?
Manasi
> > ---
> > drivers/gpu/drm/drm_atomic.c | 10 ++++++
> > drivers/gpu/drm/drm_atomic_helper.c | 8 +++++
> > drivers/gpu/drm/drm_connector.c | 61 ++++++++++++++++++++++++++++++++++++-
> > include/drm/drm_connector.h | 18 ++++++++++-
> > include/drm/drm_mode_config.h | 5 +++
> > include/uapi/drm/drm_mode.h | 4 +++
> > 6 files changed, 104 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
> > index 89737e4..990f013 100644
> > --- a/drivers/gpu/drm/drm_atomic.c
> > +++ b/drivers/gpu/drm/drm_atomic.c
> > @@ -1087,6 +1087,14 @@ int drm_atomic_connector_set_property(struct drm_connector *connector,
> > * now?) atomic writes to DPMS property:
> > */
> > return -EINVAL;
> > + } else if (property == config->link_status_property) {
> > + /* Never downgrade from GOOD to BAD on userspace's request here,
> > + * only hw issues can do that.
> > + */
> > + if (state->link_status == DRM_LINK_STATUS_GOOD)
> > + return 0;
> > + state->link_status = val;
> > + return 0;
> > } else if (connector->funcs->atomic_set_property) {
> > return connector->funcs->atomic_set_property(connector,
> > state, property, val);
> > @@ -1135,6 +1143,8 @@ static void drm_atomic_connector_print_state(struct drm_printer *p,
> > *val = (state->crtc) ? state->crtc->base.id : 0;
> > } else if (property == config->dpms_property) {
> > *val = connector->dpms;
> > + } else if (property == config->link_status_property) {
> > + *val = state->link_status;
> > } else if (connector->funcs->atomic_get_property) {
> > return connector->funcs->atomic_get_property(connector,
> > state, property, val);
> > diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> > index 494680c..962ed66 100644
> > --- a/drivers/gpu/drm/drm_atomic_helper.c
> > +++ b/drivers/gpu/drm/drm_atomic_helper.c
> > @@ -519,6 +519,13 @@ static int handle_conflicting_encoders(struct drm_atomic_state *state,
> > connector_state);
> > if (ret)
> > return ret;
> > + if (connector->state->crtc) {
> > + crtc_state = drm_atomic_get_existing_crtc_state(state,
> > + connector->state->crtc);
> > + if (connector->state->link_status !=
> > + connector_state->link_status)
> > + crtc_state->connectors_changed = true;
> > + }
>
> Why hide this here in handle_conflicting_encoders? This is a bit
> confusing. I'd move it into the connector loop in
> drm_atomic_helper_check_modeset().
> > }
> >
> > /*
> > @@ -2258,6 +2265,7 @@ static int update_output_state(struct drm_atomic_state *state,
> > NULL);
> > if (ret)
> > return ret;
> > + conn_state->link_status = DRM_LINK_STATUS_GOOD;
> > }
> > }
> >
> > diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
> > index 5a45262..cd53c39 100644
> > --- a/drivers/gpu/drm/drm_connector.c
> > +++ b/drivers/gpu/drm/drm_connector.c
> > @@ -243,6 +243,10 @@ int drm_connector_init(struct drm_device *dev,
> > drm_object_attach_property(&connector->base,
> > config->dpms_property, 0);
> >
> > + drm_object_attach_property(&connector->base,
> > + config->link_status_property,
> > + 0);
> > +
> > if (drm_core_check_feature(dev, DRIVER_ATOMIC)) {
> > drm_object_attach_property(&connector->base, config->prop_crtc_id, 0);
> > }
> > @@ -506,6 +510,12 @@ const char *drm_get_subpixel_order_name(enum subpixel_order order)
> > };
> > DRM_ENUM_NAME_FN(drm_get_dpms_name, drm_dpms_enum_list)
> >
> > +static const struct drm_prop_enum_list drm_link_status_enum_list[] = {
> > + { DRM_MODE_LINK_STATUS_GOOD, "Good" },
> > + { DRM_MODE_LINK_STATUS_BAD, "Bad" },
> > +};
> > +DRM_ENUM_NAME_FN(drm_get_link_status_name, drm_link_status_enum_list)
> > +
> > /**
> > * drm_display_info_set_bus_formats - set the supported bus formats
> > * @info: display info to store bus formats in
> > @@ -625,7 +635,14 @@ int drm_display_info_set_bus_formats(struct drm_display_info *info,
> > * tiling and virtualize both &drm_crtc and &drm_plane if needed. Drivers
> > * should update this value using drm_mode_connector_set_tile_property().
> > * Userspace cannot change this property.
> > - *
> > + * link-status:
> > + * Connector link-status property to indicate the status of link during
> > + * the modeset. The default value of link-status is "GOOD". If something
> > + * fails during modeset, the kernel driver can set this to "BAD", prune
> > + * the mode list based on new link parameters and send a hotplug uevent
> > + * to notify userspace to re-check the valid modes through GET_CONNECTOR
> > + * IOCTL and redo a modeset. Drivers should update this value using
> > + * drm_mode_connector_set_link_status_property().
>
> Please leave the empty line here after the definition list, for better
> layout. Also I thought there were some comments from Sean Paul that the
> kernel-doc was confusing, have you worked together with him to address
> this?
>
> > * Connectors also have one standardized atomic property:
> > *
> > * CRTC_ID:
> > @@ -666,6 +683,13 @@ int drm_connector_create_standard_properties(struct drm_device *dev)
> > return -ENOMEM;
> > dev->mode_config.tile_property = prop;
> >
> > + prop = drm_property_create_enum(dev, DRM_MODE_PROP_ATOMIC, "link-status",
> > + drm_link_status_enum_list,
> > + ARRAY_SIZE(drm_link_status_enum_list));
> > + if (!prop)
> > + return -ENOMEM;
> > + dev->mode_config.link_status_property = prop;
> > +
> > return 0;
> > }
> >
> > @@ -995,6 +1019,41 @@ int drm_mode_connector_update_edid_property(struct drm_connector *connector,
> > }
> > EXPORT_SYMBOL(drm_mode_connector_update_edid_property);
> >
> > +/**
> > + * drm_mode_connector_set_link_status_property - Set link status property of a connector
> > + * @connector: drm connector
> > + * @link_status: new value of link status property (0: Good, 1: Bad)
> > + *
> > + * In usual working scenario, this link status property will always be set to
> > + * "GOOD". If something fails during or after a mode set, the kernel driver should
> > + * set this link status property to "BAD" and prune the mode list based on new
> > + * information. The caller then needs to send a hotplug uevent for userspace to
> > + * re-check the valid modes through GET_CONNECTOR_IOCTL and retry modeset.
> > + *
> > + * Note that a lot of existing userspace do not handle this property.
> > + * Drivers can therefore not rely on userspace to fix up everything and
> > + * should try to handle issues (like just re-training a link) without
> > + * userspace's intervention. This should only be used when the current mode
> > + * fails and userspace must select a different display mode.
> > + * The DRM driver can chose to not modify property and keep link status
> > + * as "GOOD" always to keep the user experience same as it currently is.
> > + *
> > + * The reason for adding this property is to handle link training failures, but
> > + * it is not limited to DP or link training. For example, if we implement
> > + * asynchronous setcrtc, this property can be used to report any failures in that.
> > + */
> > +void drm_mode_connector_set_link_status_property(struct drm_connector *connector,
> > + uint64_t link_status)
> > +{
> > + struct drm_device *dev = connector->dev;
> > +
> > + drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
> > + connector->state->link_status = link_status;
> > + drm_modeset_unlock(&dev->mode_config.connection_mutex);
> > +
> > +}
> > +EXPORT_SYMBOL(drm_mode_connector_set_link_status_property);
> > +
> > int drm_mode_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 34f9741..ba22ed1 100644
> > --- a/include/drm/drm_connector.h
> > +++ b/include/drm/drm_connector.h
> > @@ -90,6 +90,17 @@ enum subpixel_order {
> > };
> >
> > /**
> > + * enum drm_link_status - connector's link_status property value
> > + *
> > + * This enum is used as the connector's link status property value.
> > + * It is set to the values defined in uapi.
> > + */
> > +enum drm_link_status {
> > + DRM_LINK_STATUS_GOOD = DRM_MODE_LINK_STATUS_GOOD,
> > + DRM_LINK_STATUS_BAD = DRM_MODE_LINK_STATUS_BAD,
> > +};
> > +
> > +/**
> > * struct drm_display_info - runtime data about the connected sink
> > *
> > * Describes a given display (e.g. CRT or flat panel) and its limitations. For
> > @@ -213,6 +224,9 @@ struct drm_connector_state {
> >
> > struct drm_encoder *best_encoder;
> >
> > + /* Connector Link status */
> > + enum drm_link_status link_status;
>
> make htmldocs should complain about the missing kernel-doc here. Just
> convert your inline comment into a proper kernel-doc:
>
> /**
> * @link_status: Connector link status
> */
>
> Also in general a comment that literally says the same as the code isn't
> useful. Comments should explain why the code does something, not what
> exactly it does - that should be self-evident.
> > +
> > struct drm_atomic_state *state;
> > };
> >
> > @@ -695,6 +709,7 @@ struct drm_connector {
> > uint8_t num_h_tile, num_v_tile;
> > uint8_t tile_h_loc, tile_v_loc;
> > uint16_t tile_h_size, tile_v_size;
> > +
>
> Spurious whitespace change, pls check for these before submitting. I think
> this one here is new.
>
> > };
> >
> > #define obj_to_connector(x) container_of(x, struct drm_connector, base)
> > @@ -767,12 +782,13 @@ int drm_mode_create_tv_properties(struct drm_device *dev,
> > int drm_mode_create_scaling_mode_property(struct drm_device *dev);
> > int drm_mode_create_aspect_ratio_property(struct drm_device *dev);
> > int drm_mode_create_suggested_offset_properties(struct drm_device *dev);
> > -
>
> Same.
>
> > int drm_mode_connector_set_path_property(struct drm_connector *connector,
> > const char *path);
> > int drm_mode_connector_set_tile_property(struct drm_connector *connector);
> > int drm_mode_connector_update_edid_property(struct drm_connector *connector,
> > const struct edid *edid);
> > +void drm_mode_connector_set_link_status_property(struct drm_connector *connector,
> > + uint64_t link_status);
> >
> > /**
> > * struct drm_tile_group - Tile group metadata
> > diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
> > index bf9991b..86faee4 100644
> > --- a/include/drm/drm_mode_config.h
> > +++ b/include/drm/drm_mode_config.h
> > @@ -431,6 +431,11 @@ struct drm_mode_config {
> > */
> > struct drm_property *tile_property;
> > /**
> > + * @link_status_property: Default connector property for link status
> > + * of a connector
> > + */
> > + struct drm_property *link_status_property;
> > + /**
> > * @plane_type_property: Default plane property to differentiate
> > * CURSOR, PRIMARY and OVERLAY legacy uses of planes.
> > */
> > diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
> > index 728790b..309c478 100644
> > --- a/include/uapi/drm/drm_mode.h
> > +++ b/include/uapi/drm/drm_mode.h
> > @@ -123,6 +123,10 @@
> > #define DRM_MODE_DIRTY_ON 1
> > #define DRM_MODE_DIRTY_ANNOTATE 2
> >
> > +/* Link Status options */
> > +#define DRM_MODE_LINK_STATUS_GOOD 0
> > +#define DRM_MODE_LINK_STATUS_BAD 1
> > +
> > struct drm_mode_modeinfo {
> > __u32 clock;
> > __u16 hdisplay;
> > --
> > 1.9.1
> >
> > _______________________________________________
> > dri-devel mailing list
> > dri-devel at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/dri-devel
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch
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