[Intel-gfx] [PATCH] drm/i915: Do not do link training fallback or prune modes for eDP

[Manasi Navare]

In case of eDP because the panel has a fixed mode we cannot
link train fallback and prune modes since this results in
no modes available for eDP connector.
Also since its a panel, link training should not fail dynamically
based on cable conditions like in  case of DP.

Cc: Jani Nikula <jani.nikula at linux.intel.com>
Cc: Jim Bride <jim.bride at linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Cc: Daniel Vetter <daniel.vetter at intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare at intel.com>
---
 drivers/gpu/drm/i915/intel_dp.c               | 2 +-
 drivers/gpu/drm/i915/intel_dp_link_training.c | 3 ++-
 drivers/gpu/drm/i915/intel_drv.h              | 1 +
 3 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 4fd4853..edac0c8 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -109,7 +109,7 @@ static const int default_rates[] = { 162000, 270000, 540000 };
  * If a CPU or PCH DP output is attached to an eDP panel, this function
  * will return true, and false otherwise.
  */
-static bool is_edp(struct intel_dp *intel_dp)
+bool is_edp(struct intel_dp *intel_dp)
 {
 	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
 
diff --git a/drivers/gpu/drm/i915/intel_dp_link_training.c b/drivers/gpu/drm/i915/intel_dp_link_training.c
index 05907fa..18ec61f 100644
--- a/drivers/gpu/drm/i915/intel_dp_link_training.c
+++ b/drivers/gpu/drm/i915/intel_dp_link_training.c
@@ -332,7 +332,8 @@ intel_dp_start_link_train(struct intel_dp *intel_dp)
 		      intel_connector->base.base.id,
 		      intel_connector->base.name,
 		      intel_dp->link_rate, intel_dp->lane_count);
-	if (!intel_dp_get_link_train_fallback_values(intel_dp,
+	/* Dont fallback and prune modes if its eDP */
+	if (!is_edp(intel_dp) && !intel_dp_get_link_train_fallback_values(intel_dp,
 						     intel_dp->link_rate,
 						     intel_dp->lane_count))
 		/* Schedule a Hotplug Uevent to userspace to start modeset */
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index fa47285..9800a15 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1548,6 +1548,7 @@ static inline unsigned int intel_dp_unused_lane_mask(int lane_count)
 }
 
 bool intel_dp_read_dpcd(struct intel_dp *intel_dp);
+bool is_edp(struct intel_dp *intel_dp);
 int intel_dp_link_required(int pixel_clock, int bpp);
 int intel_dp_max_data_rate(int max_link_clock, int max_lanes);
 bool intel_digital_port_connected(struct drm_i915_private *dev_priv,
-- 
2.1.4