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drm/amd/display: retry 3 times before successfully reading 

DPCD Extended Receiver Capability Field

[Why]
1.dpcd extended receiver capability sometimes read fail,
  and corrupted data leads to sink caps is not correct.
2.sometimes sink reply ack with fewer data

[How]
  check the return value of core_link_read_dpcd,
  try to read again when failure happens

Signed-off-by: Xiaodong Yan <Xiaodong.Yan@amd.com>
Reviewed-by: Wenjing Liu <Wenjing.Liu@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Acked-by: Tony Cheng <Tony.Cheng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Xiaodong Yan 2018-10-24 02:08:53 +08:00 committed by Alex Deucher
parent a751341961
commit 818832bf2b
1 changed files with 14 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
View File

@ -2371,11 +2371,22 @@ static bool retrieve_link_cap(struct dc_link *link)
dpcd_data[DP_TRAINING_AUX_RD_INTERVAL];
if (aux_rd_interval.bits.EXT_RECIEVER_CAP_FIELD_PRESENT == 1) {
core_link_read_dpcd(
uint8_t ext_cap_data[16];
memset(ext_cap_data, '\0', sizeof(ext_cap_data));
for (i = 0; i < read_dpcd_retry_cnt; i++) {
status = core_link_read_dpcd(
link,
DP_DP13_DPCD_REV,
dpcd_data,
sizeof(dpcd_data));
ext_cap_data,
sizeof(ext_cap_data));
if (status == DC_OK) {
memcpy(dpcd_data, ext_cap_data, sizeof(dpcd_data));
break;
}
}
if (status != DC_OK)
dm_error("%s: Read extend caps data failed, use cap from dpcd 0.\n", __func__);
}
}