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: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Dave Airlie <airlied@gmail.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1e8a710bcac46e5136c1a7b430074893c81f364a.1505203831.git.jani.nikula@intel.com

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index d9c171ce4190845950e7c14e362265b4d26adc74..9b393c29953f2c3e71abb5bce304e6bd69c3e804 100644 (file)
--- 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 c5e1a840928583d701f6965f8e978ca911eaf2e0..c9f09fc298bb0ddd5a61a3827526e5ee9000c220 100644 (file)
--- 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 df923119ac36a52197071b38b81ce7434a447970..0ee184f56a602285ad17a25c75964d99693979cc 100644 (file)
--- 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 6bb6337be920c6b440ef33f579832368feed86e5..00ddabfbf980401f8d58a4d46eff8ee60282ee5f 100644 (file)
--- 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 904966cde32b51886fc5ee9e876a1d2ec992745b..5840aabbf24e51611cb825ab6fc8b017a6ce6701 100644 (file)
--- 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 @@ 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);
-       }
+       count = (*connector_funcs->get_modes)(connector);
 
        if (count == 0 && connector->status == connector_status_connected)
                count = drm_add_modes_noedid(connector, 1024, 768);