[PATCH 4/4] drm/i915/dp: Dump DP link status when link training stages fails

[Dhinakaran Pandiyan]

A full dump of link status can be handy in debugging link training
failures. Let's add that to the debug messages when link training fails.

Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
---
 drivers/gpu/drm/i915/intel_dp_link_training.c | 11 +++++++++++
 drivers/gpu/drm/i915/intel_drv.h              |  6 ++++--
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp_link_training.c b/drivers/gpu/drm/i915/intel_dp_link_training.c
index c0a858d..ab7d1a6 100644
--- a/drivers/gpu/drm/i915/intel_dp_link_training.c
+++ b/drivers/gpu/drm/i915/intel_dp_link_training.c
@@ -24,6 +24,15 @@
 #include "intel_drv.h"
 
 static void
+intel_dp_dump_link_status(const uint8_t link_status[DP_LINK_STATUS_SIZE])
+{
+
+	DRM_DEBUG_KMS("ln0_1:0x%x ln2_3:0x%x align:0x%x sink:0x%x adj_req0_1:0x%x adj_req2_3:0x%x",
+		      link_status[0], link_status[1], link_status[2],
+		      link_status[3], link_status[4], link_status[5]);
+}
+
+static void
 intel_get_adjust_train(struct intel_dp *intel_dp,
 		       const uint8_t link_status[DP_LINK_STATUS_SIZE])
 {
@@ -170,6 +179,7 @@ intel_dp_link_training_clock_recovery(struct intel_dp *intel_dp)
 			++loop_tries;
 			if (loop_tries == 5) {
 				DRM_ERROR("too many full retries, give up\n");
+				intel_dp_dump_link_status(link_status);
 				break;
 			}
 			intel_dp_reset_link_train(intel_dp,
@@ -257,6 +267,7 @@ intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp)
 
 		if (cr_tries > 5) {
 			DRM_ERROR("failed to train DP, aborting\n");
+			intel_dp_dump_link_status(link_status);
 			break;
 		}
 
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 87069ba..549a8fd 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1356,8 +1356,6 @@ bool intel_dp_init_connector(struct intel_digital_port *intel_dig_port,
 			     struct intel_connector *intel_connector);
 void intel_dp_set_link_params(struct intel_dp *intel_dp,
 			      const struct intel_crtc_state *pipe_config);
-void intel_dp_start_link_train(struct intel_dp *intel_dp);
-void intel_dp_stop_link_train(struct intel_dp *intel_dp);
 void intel_dp_sink_dpms(struct intel_dp *intel_dp, int mode);
 void intel_dp_encoder_reset(struct drm_encoder *encoder);
 void intel_dp_encoder_suspend(struct intel_encoder *intel_encoder);
@@ -1409,6 +1407,10 @@ static inline unsigned int intel_dp_unused_lane_mask(int lane_count)
 	return ~((1 << lane_count) - 1) & 0xf;
 }
 
+/* intel_dp_link_training.c */
+void intel_dp_start_link_train(struct intel_dp *intel_dp);
+void intel_dp_stop_link_train(struct intel_dp *intel_dp);
+
 /* intel_dp_aux_backlight.c */
 int intel_dp_aux_init_backlight_funcs(struct intel_connector *intel_connector);
 
-- 
2.5.0