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authorMartin Tsai <martin.tsai@amd.com>2020-07-15 11:21:43 +0800
committerAlex Deucher <alexander.deucher@amd.com>2020-08-06 16:38:32 -0400
commit3fd20292c2352660155bbc11736dd014b2fc6e98 (patch)
tree17c160b13191a6a5a3e2492f31cbf550a693f6d2
parentbc0cd80783ff7c2201b44d384bab4629c9cb7db9 (diff)
drm/amd/display: Check lane status again after link training done
[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>
-rw-r--r--drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c50
-rw-r--r--drivers/gpu/drm/amd/display/include/link_service_types.h2
2 files changed, 52 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 5cb7b834e459..1a3dbed3becb 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
@@ -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);
diff --git a/drivers/gpu/drm/amd/display/include/link_service_types.h b/drivers/gpu/drm/amd/display/include/link_service_types.h
index 4869d4562e4d..550f46e9b95f 100644
--- a/drivers/gpu/drm/amd/display/include/link_service_types.h
+++ b/drivers/gpu/drm/amd/display/include/link_service_types.h
@@ -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 {