Commit 50d2c602 authored Jan 03, 2020 by Sung Lee Committed by Alex Deucher Jan 22, 2020

drm/amd/display: Do not send training pattern if VS Different



[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@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Abdoulaye Berthe <Abdoulaye.Berthe@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

parent 43563bc2

drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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(

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