Commit 53fd40a9 authored by Jani Nikula's avatar Jani Nikula
Browse files

drm: handle override and firmware EDID at drm_do_get_edid() level 



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@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Tested-by: default avatarAbdiel Janulgue <abdiel.janulgue@linux.intel.com>
Reviewed-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: default avatarDave Airlie <airlied@gmail.com>
Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1e8a710bcac46e5136c1a7b430074893c81f364a.1505203831.git.jani.nikula@intel.com
parent c673fe7f

Documentation/admin-guide/kernel-parameters.txt

+1 −1
Original line number Diff line number Diff line
@@ -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

drivers/gpu/drm/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -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

drivers/gpu/drm/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -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

drivers/gpu/drm/drm_edid.c

+15 −0
Original line number Diff line number Diff line
@@ -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;

drivers/gpu/drm/drm_probe_helper.c

+1 −18
Original line number Diff line number Diff line
@@ -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 @@ retry: 
		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);

	}



	if (count == 0 && connector->status == connector_status_connected)

		count = drm_add_modes_noedid(connector, 1024, 768);

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