drm/dp: Revert "drm/dp: Introduce EDID-based quirks"

This reverts commit 0883ce8146ed6074c76399f4e70dbed788582e12. Originally
these quirks were added because of the issues with using the eDP
backlight interfaces on certain laptop panels, which made it impossible
to properly probe for DPCD backlight support without having a whitelist
for panels that we know have working VESA backlight control interfaces
over DPCD. As well, it should be noted it was impossible to use the
normal sink OUI for recognizing these panels as none of them actually
filled out their OUIs, hence needing to resort to checking EDIDs.

At the time we weren't really sure why certain panels had issues with
DPCD backlight controls, but we eventually figured out that there was a
second interface that these problematic laptop panels actually did work
with and advertise properly: Intel's proprietary backlight interface for
HDR panels. So far the testing we've done hasn't brought any panels to
light that advertise this interface and don't support it properly, which
means we finally have a real solution to this problem.

As a result, we now have no need for the force DPCD backlight quirk, and
furthermore this also removes the need for any kind of EDID quirk
checking in DRM. So, let's just revert it for now since we were the only
driver using this.

v3:
* Rebase
v2:
* Fix indenting error picked up by checkpatch in
  intel_edp_init_connector()

Signed-off-by: Lyude Paul <lyude@redhat.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Cc: thaytan@noraisin.net
Cc: Vasily Khoruzhick <anarsoul@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210114221709.2261452-6-lyude@redhat.com

1 files changed, 3 insertions, 18 deletions

diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index 6236f212da61..edffd1dcca3e 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -2029,16 +2029,13 @@ struct drm_dp_desc {
 
 int drm_dp_read_desc(struct drm_dp_aux *aux, struct drm_dp_desc *desc,
 		     bool is_branch);
-u32 drm_dp_get_edid_quirks(const struct edid *edid);
 
 /**
  * enum drm_dp_quirk - Display Port sink/branch device specific quirks
  *
  * Display Port sink and branch devices in the wild have a variety of bugs, try
  * to collect them here. The quirks are shared, but it's up to the drivers to
- * implement workarounds for them. Note that because some devices have
- * unreliable OUIDs, the EDID of sinks should also be checked for quirks using
- * drm_dp_get_edid_quirks().
+ * implement workarounds for them.
  */
 enum drm_dp_quirk {
 	/**
@@ -2071,16 +2068,6 @@ enum drm_dp_quirk {
 	 */
 	DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD,
 	/**
-	 * @DP_QUIRK_FORCE_DPCD_BACKLIGHT:
-	 *
-	 * The device is telling the truth when it says that it uses DPCD
-	 * backlight controls, even if the system's firmware disagrees. This
-	 * quirk should be checked against both the ident and panel EDID.
-	 * When present, the driver should honor the DPCD backlight
-	 * capabilities advertised.
-	 */
-	DP_QUIRK_FORCE_DPCD_BACKLIGHT,
-	/**
 	 * @DP_DPCD_QUIRK_CAN_DO_MAX_LINK_RATE_3_24_GBPS:
 	 *
 	 * The device supports a link rate of 3.24 Gbps (multiplier 0xc) despite
@@ -2092,16 +2079,14 @@ enum drm_dp_quirk {
 /**
  * drm_dp_has_quirk() - does the DP device have a specific quirk
  * @desc: Device descriptor filled by drm_dp_read_desc()
- * @edid_quirks: Optional quirk bitmask filled by drm_dp_get_edid_quirks()
  * @quirk: Quirk to query for
  *
  * Return true if DP device identified by @desc has @quirk.
  */
 static inline bool
-drm_dp_has_quirk(const struct drm_dp_desc *desc, u32 edid_quirks,
-		 enum drm_dp_quirk quirk)
+drm_dp_has_quirk(const struct drm_dp_desc *desc, enum drm_dp_quirk quirk)
 {
-	return (desc->quirks | edid_quirks) & BIT(quirk);
+	return desc->quirks & BIT(quirk);
 }
 
 #ifdef CONFIG_DRM_DP_CEC