Attachment 141229 Details for Bug 107489 – version 2 of test patch

[patch] version 2 of test patch

v2-0001-drm-i915-dp-Link-train-Fallback-on-eDP-only-if-fa.patch (text/plain), 4.95 KB, created by Manasi on 2018-08-22 01:22:42 UTC

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Creator: Manasi

Created: 2018-08-22 01:22:42 UTC

Size: 4.95 KB

patch

obsolete

>From 88a37d925ba6754b06b6ddeb9de2fca79693ca3b Mon Sep 17 00:00:00 2001
>From: Manasi Navare <manasi.d.navare@intel.com>
>Date: Wed, 16 May 2018 18:37:15 -0700
>Subject: [PATCH v2] drm/i915/dp: Link train Fallback on eDP only if fallback
> link BW can fit panel's native mode
>
>This patch fixes the original commit c0cfb10d9e1de49 ("drm/i915/edp:
>Do not do link training fallback or prune modes on EDP") that causes
>a blank screen in case of certain eDP panels (Eg: seen on Dell XPS13 9350)
>where first link training fails and a retraining is required by falling
>back to lower link rate/lane count.
>In case of some panels they advertise higher link rate/lane count
>than whats required for supporting the panel's native mode.
>But we always link train at highest link rate/lane count for eDP
>and if that fails we can still fallback to lower link rate/lane count
>as long as the fallback link BW still fits the native mode to avoid
>pruning the panel's native mode yet retraining at fallback values
>to recover from a blank screen.
>
>v2:
>* Send uevent if link failure on eDP unconditionally
>
>Cc: Clinton Taylor <clinton.a.taylor@intel.com>
>Cc: Jani Nikula <jani.nikula@linux.intel.com>
>Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
>Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
>Cc: Lucas De Marchi <lucas.demarchi@intel.com>
>Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
>---
> drivers/gpu/drm/i915/intel_dp.c               | 29 +++++++++++++++++++
> drivers/gpu/drm/i915/intel_dp_link_training.c | 26 ++++++-----------
> 2 files changed, 38 insertions(+), 17 deletions(-)
>
>diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
>index 8e0e14ba534f..ae4903771978 100644
>--- a/drivers/gpu/drm/i915/intel_dp.c
>+++ b/drivers/gpu/drm/i915/intel_dp.c
>@@ -564,6 +564,21 @@ static bool intel_dp_link_params_valid(struct intel_dp *intel_dp, int link_rate,
> 	return true;
> }
> 
>+static bool intel_dp_can_link_train_fallback_for_edp(struct intel_dp *intel_dp,
>+						     int link_rate,
>+						     uint8_t lane_count)
>+{
>+	struct drm_display_mode *fixed_mode = intel_dp->attached_connector->panel.fixed_mode;
>+	int mode_rate, max_rate;
>+
>+	mode_rate = intel_dp_link_required(fixed_mode->clock, 18);
>+	max_rate = intel_dp_max_data_rate(link_rate, lane_count);
>+	if (mode_rate > max_rate)
>+		return false;
>+
>+	return true;
>+}
>+
> int intel_dp_get_link_train_fallback_values(struct intel_dp *intel_dp,
> 					    int link_rate, uint8_t lane_count)
> {
>@@ -573,9 +588,23 @@ int intel_dp_get_link_train_fallback_values(struct intel_dp *intel_dp,
> 				    intel_dp->num_common_rates,
> 				    link_rate);
> 	if (index > 0) {
>+		if (intel_dp_is_edp(intel_dp) &&
>+		    !intel_dp_can_link_train_fallback_for_edp(intel_dp,
>+							     intel_dp->common_rates[index-1],
>+							      lane_count)) {
>+			DRM_DEBUG_KMS("Retrying Link training for eDP with same parameters\n");
>+			return 0;
>+		}
> 		intel_dp->max_link_rate = intel_dp->common_rates[index - 1];
> 		intel_dp->max_link_lane_count = lane_count;
> 	} else if (lane_count > 1) {
>+		if (intel_dp_is_edp(intel_dp) &&
>+		    !intel_dp_can_link_train_fallback_for_edp(intel_dp,
>+							      intel_dp_max_common_rate(intel_dp),
>+							      lane_count >> 1)) {
>+			DRM_DEBUG_KMS("Retrying Link training for eDP with same parameters\n");
>+			return 0;
>+		}
> 		intel_dp->max_link_rate = intel_dp_max_common_rate(intel_dp);
> 		intel_dp->max_link_lane_count = lane_count >> 1;
> 	} else {
>diff --git a/drivers/gpu/drm/i915/intel_dp_link_training.c b/drivers/gpu/drm/i915/intel_dp_link_training.c
>index a9f40985a621..30be0e39bd5f 100644
>--- a/drivers/gpu/drm/i915/intel_dp_link_training.c
>+++ b/drivers/gpu/drm/i915/intel_dp_link_training.c
>@@ -367,22 +367,14 @@ intel_dp_start_link_train(struct intel_dp *intel_dp)
> 	return;
> 
>  failure_handling:
>-	/* Dont fallback and prune modes if its eDP */
>-	if (!intel_dp_is_edp(intel_dp)) {
>-		DRM_DEBUG_KMS("[CONNECTOR:%d:%s] Link Training failed at link rate = %d, lane count = %d",
>-			      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,
>-							     intel_dp->link_rate,
>-							     intel_dp->lane_count))
>-			/* Schedule a Hotplug Uevent to userspace to start modeset */
>-			schedule_work(&intel_connector->modeset_retry_work);
>-	} else {
>-		DRM_ERROR("[CONNECTOR:%d:%s] Link Training failed at link rate = %d, lane count = %d",
>-			  intel_connector->base.base.id,
>-			  intel_connector->base.name,
>-			  intel_dp->link_rate, intel_dp->lane_count);
>-	}
>+	DRM_DEBUG_KMS("[CONNECTOR:%d:%s] Link Training failed at link rate = %d, lane count = %d",
>+		      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,
>+						     intel_dp->link_rate,
>+						     intel_dp->lane_count))
>+		/* Schedule a Hotplug Uevent to userspace to start modeset */
>+		schedule_work(&intel_connector->modeset_retry_work);
> 	return;
> }
>-- 
>2.18.0
>

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Attachments on bug 107489: 141086 | 141099 | 141227 | 141229

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