From: Vladimir Stempen vladimir.stempen@amd.com
[ Upstream commit b6ef55ccba7ed00fc10e3e6f619c8f886162427f ]
[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 Signed-off-by: Sasha Levin sashal@kernel.org --- .../gpu/drm/amd/display/dc/core/dc_link_dp.c | 27 +++++++++++++++++++ 1 file changed, 27 insertions(+)
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 1b6c75a4dd60..fbcd979438e2 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 @@ -220,6 +220,30 @@ 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); @@ -252,6 +276,9 @@ 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;