[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

Signed-off-by: Sivakumar Thulasimani <sivakumar.thulasimani at intel.com>
---
 drivers/gpu/drm/i915/intel_dp.c |  117 ++++++++++++++++++++-------------------
 1 file changed, 59 insertions(+), 58 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index b905c19..e4de8e5 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -4342,6 +4342,56 @@ go_again:
 	return -EINVAL;
 }
 
+/* XXX this is probably wrong for multiple downstream ports */
+static enum drm_connector_status
+intel_dp_detect_dpcd(struct intel_dp *intel_dp)
+{
+	uint8_t *dpcd = intel_dp->dpcd;
+	uint8_t type;
+
+	if (!intel_dp_get_dpcd(intel_dp))
+		return connector_status_disconnected;
+
+	/* if there's no downstream port, we're done */
+	if (!(dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_PRESENT))
+		return connector_status_connected;
+
+	/* If we're HPD-aware, SINK_COUNT changes dynamically */
+	if (intel_dp->dpcd[DP_DPCD_REV] >= 0x11 &&
+	    intel_dp->downstream_ports[0] & DP_DS_PORT_HPD) {
+		uint8_t reg;
+
+		if (intel_dp_dpcd_read_wake(&intel_dp->aux, DP_SINK_COUNT,
+					    &reg, 1) < 0)
+			return connector_status_unknown;
+
+		return DP_GET_SINK_COUNT(reg) ? connector_status_connected
+					      : connector_status_disconnected;
+	}
+
+	/* If no HPD, poke DDC gently */
+	if (drm_probe_ddc(&intel_dp->aux.ddc))
+		return connector_status_connected;
+
+	/* Well we tried, say unknown for unreliable port types */
+	if (intel_dp->dpcd[DP_DPCD_REV] >= 0x11) {
+		type = intel_dp->downstream_ports[0] & DP_DS_PORT_TYPE_MASK;
+		if (type == DP_DS_PORT_TYPE_VGA ||
+		    type == DP_DS_PORT_TYPE_NON_EDID)
+			return connector_status_unknown;
+	} else {
+		type = intel_dp->dpcd[DP_DOWNSTREAMPORT_PRESENT] &
+			DP_DWN_STRM_PORT_TYPE_MASK;
+		if (type == DP_DWN_STRM_PORT_TYPE_ANALOG ||
+		    type == DP_DWN_STRM_PORT_TYPE_OTHER)
+			return connector_status_unknown;
+	}
+
+	/* Anything else is out of spec, warn and ignore */
+	DRM_DEBUG_KMS("Broken DP branch device, ignoring\n");
+	return connector_status_disconnected;
+}
+
 /*
  * According to DP spec
  * 5.1.2:
@@ -4362,21 +4412,22 @@ 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 &&
@@ -4401,56 +4452,6 @@ intel_dp_check_link_status(struct intel_dp *intel_dp)
 	}
 }
 
-/* XXX this is probably wrong for multiple downstream ports */
-static enum drm_connector_status
-intel_dp_detect_dpcd(struct intel_dp *intel_dp)
-{
-	uint8_t *dpcd = intel_dp->dpcd;
-	uint8_t type;
-
-	if (!intel_dp_get_dpcd(intel_dp))
-		return connector_status_disconnected;
-
-	/* if there's no downstream port, we're done */
-	if (!(dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_PRESENT))
-		return connector_status_connected;
-
-	/* If we're HPD-aware, SINK_COUNT changes dynamically */
-	if (intel_dp->dpcd[DP_DPCD_REV] >= 0x11 &&
-	    intel_dp->downstream_ports[0] & DP_DS_PORT_HPD) {
-		uint8_t reg;
-
-		if (intel_dp_dpcd_read_wake(&intel_dp->aux, DP_SINK_COUNT,
-					    &reg, 1) < 0)
-			return connector_status_unknown;
-
-		return DP_GET_SINK_COUNT(reg) ? connector_status_connected
-					      : connector_status_disconnected;
-	}
-
-	/* If no HPD, poke DDC gently */
-	if (drm_probe_ddc(&intel_dp->aux.ddc))
-		return connector_status_connected;
-
-	/* Well we tried, say unknown for unreliable port types */
-	if (intel_dp->dpcd[DP_DPCD_REV] >= 0x11) {
-		type = intel_dp->downstream_ports[0] & DP_DS_PORT_TYPE_MASK;
-		if (type == DP_DS_PORT_TYPE_VGA ||
-		    type == DP_DS_PORT_TYPE_NON_EDID)
-			return connector_status_unknown;
-	} else {
-		type = intel_dp->dpcd[DP_DOWNSTREAMPORT_PRESENT] &
-			DP_DWN_STRM_PORT_TYPE_MASK;
-		if (type == DP_DWN_STRM_PORT_TYPE_ANALOG ||
-		    type == DP_DWN_STRM_PORT_TYPE_OTHER)
-			return connector_status_unknown;
-	}
-
-	/* Anything else is out of spec, warn and ignore */
-	DRM_DEBUG_KMS("Broken DP branch device, ignoring\n");
-	return connector_status_disconnected;
-}
-
 static enum drm_connector_status
 edp_detect(struct intel_dp *intel_dp)
 {
-- 
1.7.9.5