[Intel-gfx] [PATCH 1/2] drm/i915: Read sink_count dpcd always for short hpd

[Sivakumar Thulasimani]

From: "Thulasimani,Sivakumar" <sivakumar.thulasimani at intel.com>

Compliance test 4.2.2.8 requires driver to read the sink_count for
short pulse interrupt even when the panel is not enabled.
This patch performs the following
a) reading sink_count by reusing intel_dp_detect_dpcd
instead of using intel_dp_get_dpcd
b) moving crtc enabled checks post sink_count read call

v2: avoid code movement with functionality changes (Ville)

Signed-off-by: Sivakumar Thulasimani <sivakumar.thulasimani at intel.com>
---
 drivers/gpu/drm/i915/intel_dp.c |   20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index b905c19..0b73e98 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -132,6 +132,8 @@ static void edp_panel_vdd_off(struct intel_dp *intel_dp, bool sync);
 static void vlv_init_panel_power_sequencer(struct intel_dp *intel_dp);
 static void vlv_steal_power_sequencer(struct drm_device *dev,
 				      enum pipe pipe);
+static enum drm_connector_status
+intel_dp_detect_dpcd(struct intel_dp *intel_dp);
 
 static int
 intel_dp_max_link_bw(struct intel_dp  *intel_dp)
@@ -4362,21 +4364,23 @@ intel_dp_check_link_status(struct intel_dp *intel_dp)
 
 	WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
 
-	if (!intel_encoder->base.crtc)
+	/* 4.2.2.8 requires source to read link_status, 0 - 12 DPCD &
+	 * sink_count even for short pulse irrespective of the sink is
+	 * in use or not
+	 */
+	if (!intel_dp_get_link_status(intel_dp, link_status)) {
 		return;
+	}
 
-	if (!to_intel_crtc(intel_encoder->base.crtc)->active)
+	/* reuse to read both 0 - 12 DPCD & sink_count */
+	if (intel_dp_detect_dpcd(intel_dp) != connector_status_connected)
 		return;
 
-	/* Try to read receiver status if the link appears to be up */
-	if (!intel_dp_get_link_status(intel_dp, link_status)) {
+	if (!intel_encoder->base.crtc)
 		return;
-	}
 
-	/* Now read the DPCD to see if it's actually running */
-	if (!intel_dp_get_dpcd(intel_dp)) {
+	if (!to_intel_crtc(intel_encoder->base.crtc)->active)
 		return;
-	}
 
 	/* Try to read the source of the interrupt */
 	if (intel_dp->dpcd[DP_DPCD_REV] >= 0x11 &&
-- 
1.7.9.5