[PATCH v3 1/2] drm: handle override and firmware EDID at drm_do_get_edid() level
Ville Syrjälä
ville.syrjala at linux.intel.com
Fri Sep 15 12:08:42 UTC 2017
On Tue, Sep 12, 2017 at 11:19:26AM +0300, Jani Nikula wrote:
> Handle debugfs override edid and firmware edid at the low level to
> transparently and completely replace the real edid. Previously, we
> practically only used the modes from the override EDID, and none of the
> other data, such as audio parameters.
>
> This change also prevents actual EDID reads when the EDID is to be
> overridden, but retains the DDC probe. This is useful if the reason for
> preferring override EDID are problems with reading the data, or
> corruption of the data.
>
> Move firmware EDID loading from helper to core, as the functionality
> moves to lower level as well. This will result in a change of module
> parameter from drm_kms_helper.edid_firmware to drm.edid_firmware, which
> arguably makes more sense anyway.
>
> Some future work remains related to override and firmware EDID
> validation. Like before, no validation is done for override EDID. The
> firmware EDID is validated separately in the loader. Some unification
> and deduplication would be in order, to validate all of them at the
> drm_do_get_edid() level, like "real" EDIDs.
>
> v2: move firmware loading to core
>
> v3: rebase, commit message refresh
>
> Cc: Abdiel Janulgue <abdiel.janulgue at linux.intel.com>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Signed-off-by: Jani Nikula <jani.nikula at intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
still holds
> ---
> Documentation/admin-guide/kernel-parameters.txt | 2 +-
> drivers/gpu/drm/Kconfig | 2 +-
> drivers/gpu/drm/Makefile | 2 +-
> drivers/gpu/drm/drm_edid.c | 15 +++++++++++++++
> drivers/gpu/drm/drm_probe_helper.c | 19 +------------------
> 5 files changed, 19 insertions(+), 21 deletions(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index d9c171ce4190..9b393c29953f 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -854,7 +854,7 @@
> The filter can be disabled or changed to another
> driver later using sysfs.
>
> - drm_kms_helper.edid_firmware=[<connector>:]<file>[,[<connector>:]<file>]
> + drm.edid_firmware=[<connector>:]<file>[,[<connector>:]<file>]
> Broken monitors, graphic adapters, KVMs and EDIDless
> panels may send no or incorrect EDID data sets.
> This parameter allows to specify an EDID data sets
> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> index c5e1a8409285..c9f09fc298bb 100644
> --- a/drivers/gpu/drm/Kconfig
> +++ b/drivers/gpu/drm/Kconfig
> @@ -110,7 +110,7 @@ config DRM_FBDEV_OVERALLOC
>
> config DRM_LOAD_EDID_FIRMWARE
> bool "Allow to specify an EDID data set instead of probing for it"
> - depends on DRM_KMS_HELPER
> + depends on DRM
> help
> Say Y here, if you want to use EDID data to be loaded from the
> /lib/firmware directory or one of the provided built-in
> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
> index df923119ac36..0ee184f56a60 100644
> --- a/drivers/gpu/drm/Makefile
> +++ b/drivers/gpu/drm/Makefile
> @@ -28,6 +28,7 @@ drm-$(CONFIG_DRM_PANEL) += drm_panel.o
> drm-$(CONFIG_OF) += drm_of.o
> drm-$(CONFIG_AGP) += drm_agpsupport.o
> drm-$(CONFIG_DEBUG_FS) += drm_debugfs.o drm_debugfs_crc.o
> +drm-$(CONFIG_DRM_LOAD_EDID_FIRMWARE) += drm_edid_load.o
>
> drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o drm_probe_helper.o \
> drm_plane_helper.o drm_dp_mst_topology.o drm_atomic_helper.o \
> @@ -36,7 +37,6 @@ drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o drm_probe_helper.o \
> drm_scdc_helper.o drm_gem_framebuffer_helper.o
>
> drm_kms_helper-$(CONFIG_DRM_PANEL_BRIDGE) += bridge/panel.o
> -drm_kms_helper-$(CONFIG_DRM_LOAD_EDID_FIRMWARE) += drm_edid_load.o
> drm_kms_helper-$(CONFIG_DRM_FBDEV_EMULATION) += drm_fb_helper.o
> drm_kms_helper-$(CONFIG_DRM_KMS_CMA_HELPER) += drm_fb_cma_helper.o
> drm_kms_helper-$(CONFIG_DRM_DP_AUX_CHARDEV) += drm_dp_aux_dev.o
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index 6bb6337be920..00ddabfbf980 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -1533,6 +1533,10 @@ static void connector_bad_edid(struct drm_connector *connector,
> * level, drivers must make all reasonable efforts to expose it as an I2C
> * adapter and use drm_get_edid() instead of abusing this function.
> *
> + * The EDID may be overridden using debugfs override_edid or firmare EDID
> + * (drm_load_edid_firmware() and drm.edid_firmware parameter), in this priority
> + * order. Having either of them bypasses actual EDID reads.
> + *
> * Return: Pointer to valid EDID or NULL if we couldn't find any.
> */
> struct edid *drm_do_get_edid(struct drm_connector *connector,
> @@ -1542,6 +1546,17 @@ struct edid *drm_do_get_edid(struct drm_connector *connector,
> {
> int i, j = 0, valid_extensions = 0;
> u8 *edid, *new;
> + struct edid *override = NULL;
> +
> + if (connector->override_edid)
> + override = drm_edid_duplicate((const struct edid *)
> + connector->edid_blob_ptr->data);
> +
> + if (!override)
> + override = drm_load_edid_firmware(connector);
> +
> + if (!IS_ERR_OR_NULL(override))
> + return override;
>
> if ((edid = kmalloc(EDID_LENGTH, GFP_KERNEL)) == NULL)
> return NULL;
> diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
> index 904966cde32b..5840aabbf24e 100644
> --- a/drivers/gpu/drm/drm_probe_helper.c
> +++ b/drivers/gpu/drm/drm_probe_helper.c
> @@ -353,8 +353,6 @@ EXPORT_SYMBOL(drm_helper_probe_detect);
> * drm_mode_probed_add(). New modes start their life with status as OK.
> * Modes are added from a single source using the following priority order.
> *
> - * - debugfs 'override_edid' (used for testing only)
> - * - firmware EDID (drm_load_edid_firmware())
> * - &drm_connector_helper_funcs.get_modes vfunc
> * - if the connector status is connector_status_connected, standard
> * VESA DMT modes up to 1024x768 are automatically added
> @@ -483,22 +481,7 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
> goto prune;
> }
>
> - if (connector->override_edid) {
> - struct edid *edid = (struct edid *) connector->edid_blob_ptr->data;
> -
> - count = drm_add_edid_modes(connector, edid);
> - drm_edid_to_eld(connector, edid);
> - } else {
> - struct edid *edid = drm_load_edid_firmware(connector);
> - if (!IS_ERR_OR_NULL(edid)) {
> - drm_mode_connector_update_edid_property(connector, edid);
> - count = drm_add_edid_modes(connector, edid);
> - drm_edid_to_eld(connector, edid);
> - kfree(edid);
> - }
> - if (count == 0)
> - count = (*connector_funcs->get_modes)(connector);
> - }
> + count = (*connector_funcs->get_modes)(connector);
>
> if (count == 0 && connector->status == connector_status_connected)
> count = drm_add_modes_noedid(connector, 1024, 768);
> --
> 2.11.0
--
Ville Syrjälä
Intel OTC
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