[Intel-gfx] [PATCH 3/6] drm/i915: Splitting intel_dp_check_link_status

[Shubhangi Shrivastava]

The link retraining part when EQ is not correct is
retained to intel_dp_check_link_status whereas other
operations are handled as part of intel_dp_short_pulse.
This change is required to avoid performing all DPCD
related operations on performing link retraining.

Signed-off-by: Sivakumar Thulasimani <sivakumar.thulasimani at intel.com>
Signed-off-by: Shubhangi Shrivastava <shubhangi.shrivastava at intel.com>
---
 drivers/gpu/drm/i915/intel_dp.c | 49 +++++++++++++++++++++++++----------------
 1 file changed, 30 insertions(+), 19 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 4e74cd6..92378b4 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -4421,6 +4421,31 @@ go_again:
 	return -EINVAL;
 }
 
+static void
+intel_dp_check_link_status(struct intel_dp *intel_dp)
+{
+	struct intel_encoder *intel_encoder = &dp_to_dig_port(intel_dp)->base;
+	u8 link_status[DP_LINK_STATUS_SIZE];
+
+	if (!intel_dp_get_link_status(intel_dp, link_status)) {
+		DRM_ERROR("Failed to get link status\n");
+		return;
+	}
+
+	if (!intel_encoder->base.crtc)
+		return;
+
+	if (!to_intel_crtc(intel_encoder->base.crtc)->active)
+		return;
+
+	if (!drm_dp_channel_eq_ok(link_status, intel_dp->lane_count)) {
+		DRM_DEBUG_KMS("%s: channel EQ not ok, retraining\n",
+				intel_encoder->base.name);
+		intel_dp_start_link_train(intel_dp);
+		intel_dp_stop_link_train(intel_dp);
+	}
+}
+
 /*
  * According to DP spec
  * 5.1.2:
@@ -4430,21 +4455,12 @@ go_again:
  *  4. Check link status on receipt of hot-plug interrupt
  */
 static void
-intel_dp_check_link_status(struct intel_dp *intel_dp)
+intel_dp_short_pulse(struct intel_dp *intel_dp)
 {
 	struct drm_device *dev = intel_dp_to_dev(intel_dp);
-	struct intel_encoder *intel_encoder = &dp_to_dig_port(intel_dp)->base;
 	u8 sink_irq_vector;
 	u8 link_status[DP_LINK_STATUS_SIZE];
 
-	WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
-
-	if (!intel_encoder->base.crtc)
-		return;
-
-	if (!to_intel_crtc(intel_encoder->base.crtc)->active)
-		return;
-
 	/* Try to read receiver status if the link appears to be up */
 	if (!intel_dp_get_link_status(intel_dp, link_status)) {
 		return;
@@ -4469,12 +4485,9 @@ intel_dp_check_link_status(struct intel_dp *intel_dp)
 			DRM_DEBUG_DRIVER("CP or sink specific irq unhandled\n");
 	}
 
-	if (!drm_dp_channel_eq_ok(link_status, intel_dp->lane_count)) {
-		DRM_DEBUG_KMS("%s: channel EQ not ok, retraining\n",
-			      intel_encoder->base.name);
-		intel_dp_start_link_train(intel_dp);
-		intel_dp_stop_link_train(intel_dp);
-	}
+	drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
+	intel_dp_check_link_status(intel_dp);
+	drm_modeset_unlock(&dev->mode_config.connection_mutex);
 }
 
 /* XXX this is probably wrong for multiple downstream ports */
@@ -5222,9 +5235,7 @@ intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
 		}
 
 		if (!intel_dp->is_mst) {
-			drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
-			intel_dp_check_link_status(intel_dp);
-			drm_modeset_unlock(&dev->mode_config.connection_mutex);
+			intel_dp_short_pulse(intel_dp);
 		}
 	}
 
-- 
2.6.1