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drm/amd/display: Check lane status again after link training done

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[Why]
Some monitors could suffer symbol unlock but cannot send HPD IRQ to
notic source device to handle link loss. This makes monitor stuck in
abnormal status and causes black screen.

[How]
According to the suggestion from scalar vendor, to check lane status
again after link training done. That can improve the comaptibility
from current production monitors.

Signed-off-by: Martin Tsai <martin.tsai@amd.com>
Reviewed-by: Aric Cyr <Aric.Cyr@amd.com>
Acked-by: Eryk Brol <eryk.brol@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Martin Tsai 2020-07-15 11:21:43 +08:00 committed by Alex Deucher
parent bc0cd80783
commit 3fd20292c2
2 changed files with 52 additions and 0 deletions
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50
drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
View File

@ -1133,6 +1133,45 @@ static inline enum link_training_result perform_link_training_int(
return status;
}
static enum link_training_result check_link_loss_status(
struct dc_link *link,
const struct link_training_settings *link_training_setting)
{
enum link_training_result status = LINK_TRAINING_SUCCESS;
unsigned int lane01_status_address = DP_LANE0_1_STATUS;
union lane_status lane_status;
uint8_t dpcd_buf[4] = {0};
uint32_t lane;
core_link_read_dpcd(
link,
lane01_status_address,
(uint8_t *)(dpcd_buf),
sizeof(dpcd_buf));
/*parse lane status*/
for (lane = 0; lane < link->cur_link_settings.lane_count; lane++) {
/*
* check lanes status
*/
lane_status.raw = get_nibble_at_index(&dpcd_buf[0], lane);
if (!lane_status.bits.CHANNEL_EQ_DONE_0 ||
!lane_status.bits.CR_DONE_0 ||
!lane_status.bits.SYMBOL_LOCKED_0) {
/* if one of the channel equalization, clock
* recovery or symbol lock is dropped
* consider it as (link has been
* dropped) dp sink status has changed
*/
status = LINK_TRAINING_LINK_LOSS;
break;
}
}
return status;
}
static void initialize_training_settings(
struct dc_link *link,
const struct dc_link_settings *link_setting,
@ -1372,6 +1411,9 @@ static void print_status_message(
case LINK_TRAINING_LQA_FAIL:
lt_result = "LQA failed";
break;
case LINK_TRAINING_LINK_LOSS:
lt_result = "Link loss";
break;
default:
break;
}
@ -1531,6 +1573,14 @@ enum link_training_result dc_link_dp_perform_link_training(
status);
}
/* delay 5ms after Main Link output idle pattern and then check
* DPCD 0202h.
*/
if (link->connector_signal != SIGNAL_TYPE_EDP && status == LINK_TRAINING_SUCCESS) {
msleep(5);
status = check_link_loss_status(link, &lt_settings);
}
/* 6. print status message*/
print_status_message(link, &lt_settings, status);

2
drivers/gpu/drm/amd/display/include/link_service_types.h
View File

@ -66,6 +66,8 @@ enum link_training_result {
/* other failure during EQ step */
LINK_TRAINING_EQ_FAIL_EQ,
LINK_TRAINING_LQA_FAIL,
/* one of the CR,EQ or symbol lock is dropped */
LINK_TRAINING_LINK_LOSS,
};
struct link_training_settings {