[PATCH 02/22] drm/amd/display: Do not send training pattern if VS Different

Bhawanpreet Lakha Bhawanpreet.Lakha at amd.com
Thu Jan 16 20:13:58 UTC 2020


From: Sung Lee <sung.lee at amd.com>

[Why]
The DP 1.4a Spec requires that training pattern only under certain
specific conditions. Currently driver will re-send
training pattern every time voltage swing value changes,
but that should not be the case.

[How]
Do not re-send training pattern every time VS values
are different. Only send it on the first iteration.

Signed-off-by: Sung Lee <sung.lee at amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng at amd.com>
Acked-by: Abdoulaye Berthe <Abdoulaye.Berthe at amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha at amd.com>
---
 drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
index 1bd0946829e3..3bb1b481451b 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
@@ -983,7 +983,7 @@ static enum link_training_result perform_clock_recovery_sequence(
 				offset);
 
 		/* 2. update DPCD of the receiver*/
-		if (!retries_cr)
+		if (!retry_count)
 			/* EPR #361076 - write as a 5-byte burst,
 			 * but only for the 1-st iteration.*/
 			dpcd_set_lt_pattern_and_lane_settings(
-- 
2.17.1



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