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drm/amd/display: Fixed Clock Recovery Sequence

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[Why]
When performing clock recovery, if a pre-emphasis adjustment is
requested, but voltage swing remains constant, the the retry counter
will not be reset. This can lead to prematurely failing link training.

[How]
Reset the clock recovery retry counter if an adjustment is requested
for either voltage swing or pre-emphasis.

Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Calvin Hou <Calvin.Hou@amd.com>
Signed-off-by: David Galiffi <David.Galiffi@amd.com>
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Solomon Chiu <solomon.chiu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
David Galiffi
2021-03-11 18:13:12 -05:00
committed by Alex Deucher
parent 4aa8607e25
commit 3d223c5528
1 changed files with 6 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
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@@ -1098,11 +1098,13 @@ static enum link_training_result perform_clock_recovery_sequence(
if (is_max_vs_reached(lt_settings))
break;
/* 7. same voltage*/
/* Note: VS same for all lanes,
* so comparing first lane is sufficient*/
if (lt_settings->lane_settings[0].VOLTAGE_SWING ==
/* 7. same lane settings*/
/* Note: settings are the same for all lanes,
* so comparing first lane is sufficient*/
if ((lt_settings->lane_settings[0].VOLTAGE_SWING ==
req_settings.lane_settings[0].VOLTAGE_SWING)
&& (lt_settings->lane_settings[0].PRE_EMPHASIS ==
req_settings.lane_settings[0].PRE_EMPHASIS))
retries_cr++;
else
retries_cr = 0;