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From b22141c0736ee943fc013f0f90a14c830875f192 Mon Sep 17 00:00:00 2001
From: Xiaodong Yan <Xiaodong.Yan@amd.com>
Date: Wed, 24 Oct 2018 02:08:53 +0800
Subject: [PATCH 0806/2940] 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>
---
.../gpu/drm/amd/display/dc/core/dc_link_dp.c | 17 ++++++++++++++---
1 file changed, 14 insertions(+), 3 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 d91df5ef0cb3..4d1f8ac069c1 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
@@ -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__);
}
}
--
2.17.1
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