diff options
Diffstat (limited to 'drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c')
| -rw-r--r-- | drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 12 |
1 files changed, 12 insertions, 0 deletions
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 1ee544a32ebb..65d6caedbd82 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 @@ -2361,6 +2361,7 @@ static bool retrieve_link_cap(struct dc_link *link) /*Only need to read 1 byte starting from DP_DPRX_FEATURE_ENUMERATION_LIST. */ uint8_t dpcd_dprx_data = '\0'; + uint8_t dpcd_power_state = '\0'; struct dp_device_vendor_id sink_id; union down_stream_port_count down_strm_port_count; @@ -2377,6 +2378,17 @@ static bool retrieve_link_cap(struct dc_link *link) memset(&edp_config_cap, '\0', sizeof(union edp_configuration_cap)); + status = core_link_read_dpcd(link, DP_SET_POWER, + &dpcd_power_state, sizeof(dpcd_power_state)); + + /* Delay 1 ms if AUX CH is in power down state. Based on spec + * section 2.3.1.2, if AUX CH may be powered down due to + * write to DPCD 600h = 2. Sink AUX CH is monitoring differential + * signal and may need up to 1 ms before being able to reply. + */ + if (status != DC_OK || dpcd_power_state == DP_SET_POWER_D3) + udelay(1000); + for (i = 0; i < read_dpcd_retry_cnt; i++) { status = core_link_read_dpcd( link, |