[Intel-gfx] [PATCH] drm/i915: fix checksum write for automated test reply

[Sivakumar Thulasimani]

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

DP spec requires the checksum of the last block read to be written
when replying to TEST_EDID_READ. This patch fixes the current code
to do the same.

Signed-off-by: Sivakumar Thulasimani <sivakumar.thulasimani at intel.com>
---
 drivers/gpu/drm/i915/intel_dp.c |   11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index f1b9f93..9617d04 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -4090,9 +4090,18 @@ static uint8_t intel_dp_autotest_edid(struct intel_dp *intel_dp)
 				      intel_dp->aux.i2c_defer_count);
 		intel_dp->compliance_test_data = INTEL_DP_RESOLUTION_FAILSAFE;
 	} else {
+		struct edid *block = intel_connector->detect_edid;
+		uint8_t temp = intel_connector->detect_edid->extensions;
+
+		/* We have to write the checksum
+		 * of the last block read
+		 */
+		while (temp--)
+			block++;
+
 		if (!drm_dp_dpcd_write(&intel_dp->aux,
 					DP_TEST_EDID_CHECKSUM,
-					&intel_connector->detect_edid->checksum,
+					&block->checksum,
 					1))
 			DRM_DEBUG_KMS("Failed to write EDID checksum\n");
 
-- 
1.7.9.5