Commit 09f08c6c authored by Imre Deak's avatar Imre Deak
Browse files

drm/i915/dp: Add debugfs entry to force link retrain 



Add a connector debugfs entry to force retrain an active link. This can
be used to test both custom link parameters (previously forced via the
force_link_rate/lane_count entries) or link train failure scenarios
(previously forced via the force_link_training_failure entry). The entry
will autoreset after the link-retrain is complete.

v2: Add the entry from intel_dp_link_training.c (Jani)
v3: Lock connection_mutex only for the required intel_dp state. (Ville)

Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: default avatarImre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240610164933.2947366-21-imre.deak@intel.com
parent 0e0af7e0

drivers/gpu/drm/i915/display/intel_display_types.h

+1 −0
Original line number Diff line number Diff line
@@ -1777,6 +1777,7 @@ struct intel_dp { 
		/* Sequential link training failures after a passing LT */

		int seq_train_failures;

		int force_train_failure;

		bool force_retrain;

	} link;

	bool reset_link_params;

	int mso_link_count;

drivers/gpu/drm/i915/display/intel_dp.c

+13 −5
Original line number Diff line number Diff line
@@ -5065,7 +5065,7 @@ intel_dp_check_mst_status(struct intel_dp *intel_dp) 
			drm_dp_mst_hpd_irq_send_new_request(&intel_dp->mst_mgr);

	}



	if (!link_ok)

	if (!link_ok || intel_dp->link.force_retrain)

		intel_encoder_link_check_queue_work(encoder, 0);



	return !reprobe_needed;
@@ -5114,6 +5114,9 @@ intel_dp_needs_link_retrain(struct intel_dp *intel_dp) 
	if (intel_psr_enabled(intel_dp))

		return false;



	if (intel_dp->link.force_retrain)

		return true;



	if (drm_dp_dpcd_read_phy_link_status(&intel_dp->aux, DP_PHY_DPRX,

					     link_status) < 0)

		return false;
@@ -5252,8 +5255,9 @@ static int intel_dp_retrain_link(struct intel_encoder *encoder, 
	if (!intel_dp_needs_link_retrain(intel_dp))

		return 0;



	drm_dbg_kms(&dev_priv->drm, "[ENCODER:%d:%s] retraining link\n",

		    encoder->base.base.id, encoder->base.name);

	drm_dbg_kms(&dev_priv->drm, "[ENCODER:%d:%s] retraining link (forced %s)\n",

		    encoder->base.base.id, encoder->base.name,

		    str_yes_no(intel_dp->link.force_retrain));



	for_each_intel_crtc_in_pipe_mask(&dev_priv->drm, crtc, pipe_mask) {

		const struct intel_crtc_state *crtc_state =
@@ -5281,7 +5285,7 @@ static int intel_dp_retrain_link(struct intel_encoder *encoder, 
				    encoder->base.base.id, encoder->base.name,

				    ERR_PTR(ret));



		return ret;

		goto out;

	}



	for_each_intel_crtc_in_pipe_mask(&dev_priv->drm, crtc, pipe_mask) {
@@ -5308,7 +5312,11 @@ static int intel_dp_retrain_link(struct intel_encoder *encoder, 
							      intel_crtc_pch_transcoder(crtc), true);

	}



	return 0;

out:

	if (ret != -EDEADLK)

		intel_dp->link.force_retrain = false;



	return ret;

}



void intel_dp_link_check(struct intel_encoder *encoder)

drivers/gpu/drm/i915/display/intel_dp_link_training.c

+45 −0
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ 
#include "intel_dp.h"

#include "intel_dp_link_training.h"

#include "intel_encoder.h"

#include "intel_hotplug.h"

#include "intel_panel.h"



#define LT_MSG_PREFIX			"[CONNECTOR:%d:%s][ENCODER:%d:%s][%s] "
@@ -1856,6 +1857,47 @@ DEFINE_DEBUGFS_ATTRIBUTE(i915_dp_force_link_training_failure_fops, 
			 i915_dp_force_link_training_failure_show,

			 i915_dp_force_link_training_failure_write, "%llu\n");



static int i915_dp_force_link_retrain_show(void *data, u64 *val)

{

	struct intel_connector *connector = to_intel_connector(data);

	struct drm_i915_private *i915 = to_i915(connector->base.dev);

	struct intel_dp *intel_dp = intel_connector_to_intel_dp(connector);

	int err;



	err = drm_modeset_lock_single_interruptible(&i915->drm.mode_config.connection_mutex);

	if (err)

		return err;



	*val = intel_dp->link.force_retrain;



	drm_modeset_unlock(&i915->drm.mode_config.connection_mutex);



	return 0;

}



static int i915_dp_force_link_retrain_write(void *data, u64 val)

{

	struct intel_connector *connector = to_intel_connector(data);

	struct drm_i915_private *i915 = to_i915(connector->base.dev);

	struct intel_dp *intel_dp = intel_connector_to_intel_dp(connector);

	int err;



	err = drm_modeset_lock_single_interruptible(&i915->drm.mode_config.connection_mutex);

	if (err)

		return err;



	intel_dp->link.force_retrain = val;



	drm_modeset_unlock(&i915->drm.mode_config.connection_mutex);



	intel_hpd_trigger_irq(dp_to_dig_port(intel_dp));



	return 0;

}

DEFINE_DEBUGFS_ATTRIBUTE(i915_dp_force_link_retrain_fops,

			 i915_dp_force_link_retrain_show,

			 i915_dp_force_link_retrain_write, "%llu\n");



void intel_dp_link_training_debugfs_add(struct intel_connector *connector)

{

	struct dentry *root = connector->base.debugfs_entry;
@@ -1878,4 +1920,7 @@ void intel_dp_link_training_debugfs_add(struct intel_connector *connector) 


	debugfs_create_file("i915_dp_force_link_training_failure", 0644, root,

			    connector, &i915_dp_force_link_training_failure_fops);



	debugfs_create_file("i915_dp_force_link_retrain", 0644, root,

			    connector, &i915_dp_force_link_retrain_fops);

}