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drm/amd/display: DP training to set properly SCRAMBLING_DISABLE 

[Why]
DP training sequence to set SCRAMBLING_DISABLE bit properly based on
training pattern - per DP Spec.

[How]
Update dpcd_pattern.v1_4.SCRAMBLING_DISABLE with 1 for TPS1, TPS2, TPS3,
but not for TPS4.

Signed-off-by: Vladimir Stempen <vladimir.stempen@amd.com>
Reviewed-by: Wenjing Liu <Wenjing.Liu@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Vladimir Stempen 2020-04-28 13:04:35 -04:00 committed by Alex Deucher
parent c38606ab12
commit 7d1ee78f03
1 changed files with 27 additions and 0 deletions
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27
drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
View File

@ -219,6 +219,30 @@ static enum dpcd_training_patterns
return dpcd_tr_pattern;
}
static uint8_t dc_dp_initialize_scrambling_data_symbols(
struct dc_link *link,
enum dc_dp_training_pattern pattern)
{
uint8_t disable_scrabled_data_symbols = 0;
switch (pattern) {
case DP_TRAINING_PATTERN_SEQUENCE_1:
case DP_TRAINING_PATTERN_SEQUENCE_2:
case DP_TRAINING_PATTERN_SEQUENCE_3:
disable_scrabled_data_symbols = 1;
break;
case DP_TRAINING_PATTERN_SEQUENCE_4:
disable_scrabled_data_symbols = 0;
break;
default:
ASSERT(0);
DC_LOG_HW_LINK_TRAINING("%s: Invalid HW Training pattern: %d\n",
__func__, pattern);
break;
}
return disable_scrabled_data_symbols;
}
static inline bool is_repeater(struct dc_link *link, uint32_t offset)
{
return (!link->is_lttpr_mode_transparent && offset != 0);
@ -251,6 +275,9 @@ static void dpcd_set_lt_pattern_and_lane_settings(
dpcd_pattern.v1_4.TRAINING_PATTERN_SET =
dc_dp_training_pattern_to_dpcd_training_pattern(link, pattern);
dpcd_pattern.v1_4.SCRAMBLING_DISABLE =
dc_dp_initialize_scrambling_data_symbols(link, pattern);
dpcd_lt_buffer[DP_TRAINING_PATTERN_SET - DP_TRAINING_PATTERN_SET]
= dpcd_pattern.raw;