If link training at a link rate optimal for a particular mode fails during modeset's atomic commit phase, then we let the modeset complete and then retry. We save the link rate value at which link training failed, update the link status property to "BAD" and use a lower link rate to prune the modes. It will redo the modeset on the current mode at lower link rate or if the current mode gets pruned due to lower link constraints then, it will send a hotplug uevent for userspace to handle it.
This is also required to pass DP CTS tests 4.3.1.3, 4.3.1.4, 4.3.1.6.
v9: * Use the trimmed max values of link rate/lane count based on link train fallback (Daniel Vetter) v8: * Set link_status to BAD first and then call mode_valid (Jani Nikula) v7: Remove the redundant variable in previous patch itself v6: * Obtain link rate index from fallback_link_rate using the helper intel_dp_link_rate_index (Jani Nikula) * Include fallback within intel_dp_start_link_train (Jani Nikula) v5: * Move set link status to drm core (Daniel Vetter, Jani Nikula) v4: * Add fallback support for non DDI platforms too * Set connector->link status inside set_link_status function (Jani Nikula) v3: * Set link status property to BAd unconditionally (Jani Nikula) * Dont use two separate variables link_train_failed and link_status to indicate same thing (Jani Nikula) v2: * Squashed a few patches (Jani Nikula)
Acked-by: Tony Cheng tony.cheng@amd.com Acked-by: Harry Wentland Harry.wentland@amd.com Cc: Jani Nikula jani.nikula@linux.intel.com Cc: Daniel Vetter daniel.vetter@intel.com Cc: Ville Syrjala ville.syrjala@linux.intel.com Signed-off-by: Manasi Navare manasi.d.navare@intel.com --- drivers/gpu/drm/i915/intel_dp.c | 27 +++++++++++++++++++++++++++ drivers/gpu/drm/i915/intel_dp_link_training.c | 22 ++++++++++++++++++++-- drivers/gpu/drm/i915/intel_drv.h | 3 +++ 3 files changed, 50 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index b5c7526f..404da32 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -5676,6 +5676,29 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp, return false; }
+static void intel_dp_modeset_retry_work_fn(struct work_struct *work) +{ + struct intel_connector *intel_connector; + struct drm_connector *connector; + + intel_connector = container_of(work, typeof(*intel_connector), + modeset_retry_work); + connector = &intel_connector->base; + DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n", connector->base.id, + connector->name); + + /* Grab the locks before changing connector property*/ + mutex_lock(&connector->dev->mode_config.mutex); + /* Set connector link status to BAD and send a Uevent to notify + * userspace to do a modeset. + */ + drm_mode_connector_set_link_status_property(connector, + DRM_MODE_LINK_STATUS_BAD); + mutex_unlock(&connector->dev->mode_config.mutex); + /* Send Hotplug uevent so userspace can reprobe */ + drm_kms_helper_hotplug_event(connector->dev); +} + bool intel_dp_init_connector(struct intel_digital_port *intel_dig_port, struct intel_connector *intel_connector) @@ -5688,6 +5711,10 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp, enum port port = intel_dig_port->port; int type;
+ /* Initialize the work for modeset in case of link train failure */ + INIT_WORK(&intel_connector->modeset_retry_work, + intel_dp_modeset_retry_work_fn); + if (WARN(intel_dig_port->max_lanes < 1, "Not enough lanes (%d) for DP on port %c\n", intel_dig_port->max_lanes, port_name(port))) diff --git a/drivers/gpu/drm/i915/intel_dp_link_training.c b/drivers/gpu/drm/i915/intel_dp_link_training.c index 0048b52..955b239 100644 --- a/drivers/gpu/drm/i915/intel_dp_link_training.c +++ b/drivers/gpu/drm/i915/intel_dp_link_training.c @@ -313,6 +313,24 @@ void intel_dp_stop_link_train(struct intel_dp *intel_dp) void intel_dp_start_link_train(struct intel_dp *intel_dp) { - intel_dp_link_training_clock_recovery(intel_dp); - intel_dp_link_training_channel_equalization(intel_dp); + struct intel_connector *intel_connector = intel_dp->attached_connector; + + if (!intel_dp_link_training_clock_recovery(intel_dp)) + goto failure_handling; + if (!intel_dp_link_training_channel_equalization(intel_dp)) + goto failure_handling; + + DRM_DEBUG_KMS("Link Training Passed at Link Rate = %d, Lane count = %d", + intel_dp->link_rate, intel_dp->lane_count); + return; + + failure_handling: + DRM_DEBUG_KMS("Link Training failed at link rate = %d, lane count = %d", + 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; } diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h index 47e3671..9d6f7ee 100644 --- a/drivers/gpu/drm/i915/intel_drv.h +++ b/drivers/gpu/drm/i915/intel_drv.h @@ -315,6 +315,9 @@ struct intel_connector { void *port; /* store this opaque as its illegal to dereference it */
struct intel_dp *mst_port; + + /* Work struct to schedule a uevent on link train failure */ + struct work_struct modeset_retry_work; };
struct dpll {