From c0cfb10d9e1de490e36d3b9d4228c0ea0ca30677 Mon Sep 17 00:00:00 2001 From: Manasi Navare Date: Thu, 12 Oct 2017 12:13:38 -0700 Subject: [PATCH] drm/i915/edp: Do not do link training fallback or prune modes on EDP In case of eDP because the panel has a fixed mode, the link rate and lane count at which it is trained corresponds to the link BW required to support the native resolution of the panel. In case of panles with lower resolutions where fewer lanes are hooked up internally, that number is reflected in the MAX_LANE_COUNT DPCD register of the panel. So it is pointless to fallback to lower link rate/lane count in case of link training failure on eDP connector since the lower link BW will not support the native resolution of the panel and we cannot prune the preferred mode on the eDP connector. In case of Link training failure on the eDP panel, something is wrong in the HW internally and hence driver errors out with a loud and clear DRM_ERROR message. v2: * Fix the DEBUG_ERROR and add {} in else (Ville Syrjala) Cc: Clinton Taylor Cc: Jim Bride Cc: Jani Nikula Cc: Ville Syrjala Cc: Dave Airlie Cc: Daniel Vetter Signed-off-by: Manasi Navare Reviewed-by: Ville Syrjala Reference: https://bugs.freedesktop.org/show_bug.cgi?id=103369 Signed-off-by: Imre Deak Link: https://patchwork.freedesktop.org/patch/msgid/1507835618-23051-1-git-send-email-manasi.d.navare@intel.com --- drivers/gpu/drm/i915/intel_dp_link_training.c | 26 ++++++++++++------- 1 file changed, 17 insertions(+), 9 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_dp_link_training.c b/drivers/gpu/drm/i915/intel_dp_link_training.c index 05907fa8a553..cf8fef8b6f58 100644 --- a/drivers/gpu/drm/i915/intel_dp_link_training.c +++ b/drivers/gpu/drm/i915/intel_dp_link_training.c @@ -328,14 +328,22 @@ intel_dp_start_link_train(struct intel_dp *intel_dp) return; failure_handling: - 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); + /* 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); + } return; } -- 2.30.2