drm/amd/display: allow DP RX to use more cr aux rd interval delay

[why]
Regression is caused by previous change with attempt to correct the
extended cr aux rd interval delay due to mis interpretation of the DP specs.
The change turns out not working well with certain RXs.
So we decided to keep the cr aux rd interval logic as before.

Signed-off-by: Wenjing Liu <wenjing.liu@amd.com>
Reviewed-by: George Shen <George.Shen@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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 b9b66db8332b9c7264634fdf2f5827a3724fa18d..ff1e9963ec7a2b82e6233ab69c4376a2895132d3 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
@@ -49,6 +49,23 @@ static struct dc_link_settings get_common_supported_link_settings(
                struct dc_link_settings link_setting_a,
                struct dc_link_settings link_setting_b);
 
+static uint32_t get_cr_training_aux_rd_interval(struct dc_link *link,
+               const struct dc_link_settings *link_settings)
+{
+       union training_aux_rd_interval training_rd_interval;
+       uint32_t wait_in_micro_secs = 100;
+
+       memset(&training_rd_interval, 0, sizeof(training_rd_interval));
+       core_link_read_dpcd(
+                       link,
+                       DP_TRAINING_AUX_RD_INTERVAL,
+                       (uint8_t *)&training_rd_interval,
+                       sizeof(training_rd_interval));
+       if (training_rd_interval.bits.TRAINIG_AUX_RD_INTERVAL)
+               wait_in_micro_secs = training_rd_interval.bits.TRAINIG_AUX_RD_INTERVAL * 4000;
+       return wait_in_micro_secs;
+}
+
 static uint32_t get_eq_training_aux_rd_interval(
        struct dc_link *link,
        const struct dc_link_settings *link_settings)
@@ -1247,7 +1264,7 @@ static void initialize_training_settings(
        if (overrides->cr_pattern_time != NULL)
                lt_settings->cr_pattern_time = *overrides->cr_pattern_time;
        else
-               lt_settings->cr_pattern_time = 100;
+               lt_settings->cr_pattern_time = get_cr_training_aux_rd_interval(link, link_setting);
 
        if (overrides->eq_pattern_time != NULL)
                lt_settings->eq_pattern_time = *overrides->eq_pattern_time;