Commit 0e0af7e0 authored by Imre Deak's avatar Imre Deak
Browse files

drm/i915/dp: Add debugfs entry to force link training failure 



Add a connector debugfs entry to force a failure during the following
1-2 link training. The entry will auto-reset after the specified link
training events are 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/20240610164933.2947366-20-imre.deak@intel.com
parent fe089d5b

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

+1 −0
Original line number Diff line number Diff line
@@ -1776,6 +1776,7 @@ struct intel_dp { 
		bool retrain_disabled;

		/* Sequential link training failures after a passing LT */

		int seq_train_failures;

		int force_train_failure;

	} link;

	bool reset_link_params;

	int mso_link_count;

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

+53 −2
Original line number Diff line number Diff line
@@ -1504,7 +1504,10 @@ void intel_dp_start_link_train(struct intel_atomic_state *state, 
	else

		passed = intel_dp_link_train_all_phys(intel_dp, crtc_state, lttpr_count);



	if (passed) {

	if (intel_dp->link.force_train_failure) {

		intel_dp->link.force_train_failure--;

		lt_dbg(intel_dp, DP_PHY_DPRX, "Forcing link training failure\n");

	} else if (passed) {

		intel_dp->link.seq_train_failures = 0;

		intel_encoder_link_check_queue_work(encoder, 2000);

		return;
@@ -1539,7 +1542,10 @@ void intel_dp_start_link_train(struct intel_atomic_state *state, 


	intel_dp->link.retrain_disabled = true;



	if (!passed)

		lt_err(intel_dp, DP_PHY_DPRX, "Can't reduce link training parameters after failure\n");

	else

		lt_dbg(intel_dp, DP_PHY_DPRX, "Can't reduce link training parameters after forced failure\n");

}



void intel_dp_128b132b_sdp_crc16(struct intel_dp *intel_dp,
@@ -1808,6 +1814,48 @@ static int i915_dp_max_lane_count_show(void *data, u64 *val) 
}

DEFINE_DEBUGFS_ATTRIBUTE(i915_dp_max_lane_count_fops, i915_dp_max_lane_count_show, NULL, "%llu\n");



static int i915_dp_force_link_training_failure_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_train_failure;



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



	return 0;

}



static int i915_dp_force_link_training_failure_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;



	if (val > 2)

		return -EINVAL;



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

	if (err)

		return err;



	intel_dp->link.force_train_failure = val;



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



	return 0;

}

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");



void intel_dp_link_training_debugfs_add(struct intel_connector *connector)

{

	struct dentry *root = connector->base.debugfs_entry;
@@ -1827,4 +1875,7 @@ void intel_dp_link_training_debugfs_add(struct intel_connector *connector) 


	debugfs_create_file("i915_dp_max_lane_count", 0444, root,

			    connector, &i915_dp_max_lane_count_fops);



	debugfs_create_file("i915_dp_force_link_training_failure", 0644, root,

			    connector, &i915_dp_force_link_training_failure_fops);

}