[PATCH 2/2] drm/i915/edp: Use max link rate and lane count if eDP EDID quirk

[Manasi Navare]

Some eDP 1.4 panels cannot use the optimized fast and narrow pipe
config approach, but they need to use th maximum supported lane count
for the link training to succeed.
There is a DRM EDID quirk for such panels that gets set after reading
their corresponding EDID.
So if it is set, this patch forces the max lane count in compute_config()
hook to use max lane count for link training.

Cc: Clint Taylor <Clinton.A.Taylor at intel.com>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Tested-by: Albert Astals Cid <aacid at kde.org>
Tested-by: Emanuele Panigati <ilpanich at gmail.com>
Tested-by: Ralgor <ralgorfdb at compuspex.org>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109959
Signed-off-by: Manasi Navare <manasi.d.navare at intel.com>
---
 drivers/gpu/drm/i915/intel_dp.c  | 5 ++++-
 drivers/gpu/drm/i915/intel_drv.h | 3 +++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 72c49070ed14..421db00f5792 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -2028,7 +2028,8 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
 	limits.min_bpp = 6 * 3;
 	limits.max_bpp = intel_dp_compute_bpp(intel_dp, pipe_config);
 
-	if (intel_dp_is_edp(intel_dp) && intel_dp->edp_dpcd[0] < DP_EDP_14) {
+	if (intel_dp->edp_force_max_lane_count || (intel_dp_is_edp(intel_dp) &&
+						   intel_dp->edp_dpcd[0] < DP_EDP_14)) {
 		/*
 		 * Use the maximum clock and number of lanes the eDP panel
 		 * advertizes being capable of. The eDP 1.3 and earlier panels
@@ -7101,6 +7102,8 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp,
 	edid = drm_get_edid(connector, &intel_dp->aux.ddc);
 	if (edid) {
 		if (drm_add_edid_modes(connector, edid)) {
+			if (connector->display_info.force_max_lane_count)
+				intel_dp->edp_force_max_lane_count = true;
 			drm_connector_update_edid_property(connector,
 								edid);
 		} else {
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index f8c7b291fdc3..c67c3c518714 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1327,6 +1327,9 @@ struct intel_dp {
 
 	/* Display stream compression testing */
 	bool force_dsc_en;
+
+	/* eDP 1.4 EDID quirk to use max lane count */
+	bool edp_force_max_lane_count;
 };
 
 enum lspcon_vendor {
-- 
2.19.1