[Intel-gfx] [PATCH 04/13] drm/i915: Add EDID read in intel_dp_check_link_status() for Link CTS 4.2.2.1

[Todd Previte]

Adds in an EDID read after the DPCD read to accommodate test 4.2.2.1 in the
Displayport Link CTS Core 1.2 rev1.1. This test requires an EDID read for
all HPD plug events. To reduce the amount of code, this EDID read is also
used for Link CTS tests 4.2.2.3, 4.2.2.4, 4.2.2.5 and 4.2.2.6. Actual
support for these tests is implemented in later patches in this series.

V2:
- Fixed compilation error introduced during rework

Signed-off-by: Todd Previte <tprevite at gmail.com>
---
 drivers/gpu/drm/i915/intel_dp.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 23184b0..75df3e2 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -3890,6 +3890,9 @@ intel_dp_check_link_status(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;
+	struct drm_connector *connector = &intel_dp->attached_connector->base;
+	struct i2c_adapter *adapter = &intel_dp->aux.ddc;
+	struct edid *edid_read = NULL;
 	u8 sink_irq_vector;
 	u8 link_status[DP_LINK_STATUS_SIZE];
 
@@ -3906,6 +3909,14 @@ intel_dp_check_link_status(struct intel_dp *intel_dp)
 		return;
 	}
 
+	/* Displayport Link CTS Core 1.2 rev1.1 EDID testing
+	 * 4.2.2.1 - EDID read required for all HPD events
+         */
+        edid_read = drm_get_edid(connector, adapter);
+        if (!edid_read) {
+                DRM_DEBUG_DRIVER("Invalid EDID detected\n");
+        }
+
 	/* Try to read the source of the interrupt */
 	if (intel_dp->dpcd[DP_DPCD_REV] >= 0x11 &&
 	    intel_dp_get_sink_irq(intel_dp, &sink_irq_vector)) {
-- 
1.9.1