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drm/amd/display: Update Link Training Fallback logic

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[Description]
When CR fails to minimum link rate,
we should reduce lane count to the number lowest cr_done lanes.

[Code Review]
Jun Lei

Signed-off-by: Wenjing Liu <Wenjing.Liu@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Wenjing Liu 2018-02-16 14:04:16 -05:00 committed by Alex Deucher
parent 85075fa042
commit 94405cf638
3 changed files with 79 additions and 25 deletions
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98
drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
View file

@ -709,6 +709,22 @@ static enum hw_dp_training_pattern get_supported_tp(struct dc_link *link)
return HW_DP_TRAINING_PATTERN_2;
}
static enum link_training_result get_cr_failure(enum dc_lane_count ln_count,
union lane_status *dpcd_lane_status)
{
enum link_training_result result = LINK_TRAINING_SUCCESS;
if (ln_count >= LANE_COUNT_ONE && !dpcd_lane_status[0].bits.CR_DONE_0)
result = LINK_TRAINING_CR_FAIL_LANE0;
else if (ln_count >= LANE_COUNT_TWO && !dpcd_lane_status[1].bits.CR_DONE_0)
result = LINK_TRAINING_CR_FAIL_LANE1;
else if (ln_count >= LANE_COUNT_FOUR && !dpcd_lane_status[2].bits.CR_DONE_0)
result = LINK_TRAINING_CR_FAIL_LANE23;
else if (ln_count >= LANE_COUNT_FOUR && !dpcd_lane_status[3].bits.CR_DONE_0)
result = LINK_TRAINING_CR_FAIL_LANE23;
return result;
}
static enum link_training_result perform_channel_equalization_sequence(
struct dc_link *link,
struct link_training_settings *lt_settings)
@ -771,7 +787,7 @@ static enum link_training_result perform_channel_equalization_sequence(
}
static bool perform_clock_recovery_sequence(
static enum link_training_result perform_clock_recovery_sequence(
struct dc_link *link,
struct link_training_settings *lt_settings)
{
@ -846,11 +862,11 @@ static bool perform_clock_recovery_sequence(
/* 5. check CR done*/
if (is_cr_done(lane_count, dpcd_lane_status))
return true;
return LINK_TRAINING_SUCCESS;
/* 6. max VS reached*/
if (is_max_vs_reached(lt_settings))
return false;
break;
/* 7. same voltage*/
/* Note: VS same for all lanes,
@ -876,13 +892,13 @@ static bool perform_clock_recovery_sequence(
}
return false;
return get_cr_failure(lane_count, dpcd_lane_status);
}
static inline bool perform_link_training_int(
static inline enum link_training_result perform_link_training_int(
struct dc_link *link,
struct link_training_settings *lt_settings,
bool status)
enum link_training_result status)
{
union lane_count_set lane_count_set = { {0} };
union dpcd_training_pattern dpcd_pattern = { {0} };
@ -903,9 +919,9 @@ static inline bool perform_link_training_int(
get_supported_tp(link) == HW_DP_TRAINING_PATTERN_4)
return status;
if (status &&
if (status == LINK_TRAINING_SUCCESS &&
perform_post_lt_adj_req_sequence(link, lt_settings) == false)
status = false;
status = LINK_TRAINING_LQA_FAIL;
lane_count_set.bits.LANE_COUNT_SET = lt_settings->link_settings.lane_count;
lane_count_set.bits.ENHANCED_FRAMING = 1;
@ -928,6 +944,8 @@ enum link_training_result dc_link_dp_perform_link_training(
enum link_training_result status = LINK_TRAINING_SUCCESS;
char *link_rate = "Unknown";
char *lt_result = "Unknown";
struct link_training_settings lt_settings;
memset(&lt_settings, '\0', sizeof(lt_settings));
@ -951,22 +969,16 @@ enum link_training_result dc_link_dp_perform_link_training(
/* 2. perform link training (set link training done
* to false is done as well)*/
if (!perform_clock_recovery_sequence(link, &lt_settings)) {
status = LINK_TRAINING_CR_FAIL;
} else {
status = perform_clock_recovery_sequence(link, &lt_settings);
if (status == LINK_TRAINING_SUCCESS) {
status = perform_channel_equalization_sequence(link,
&lt_settings);
}
if ((status == LINK_TRAINING_SUCCESS) || !skip_video_pattern) {
if (!perform_link_training_int(link,
status = perform_link_training_int(link,
&lt_settings,
status == LINK_TRAINING_SUCCESS)) {
/* the next link training setting in this case
* would be the same as CR failure case.
*/
status = LINK_TRAINING_CR_FAIL;
}
status);
}
/* 6. print status message*/
@ -991,13 +1003,37 @@ enum link_training_result dc_link_dp_perform_link_training(
break;
}
switch (status) {
case LINK_TRAINING_SUCCESS:
lt_result = "pass";
break;
case LINK_TRAINING_CR_FAIL_LANE0:
lt_result = "CR failed lane0";
break;
case LINK_TRAINING_CR_FAIL_LANE1:
lt_result = "CR failed lane1";
break;
case LINK_TRAINING_CR_FAIL_LANE23:
lt_result = "CR failed lane23";
break;
case LINK_TRAINING_EQ_FAIL_CR:
lt_result = "CR failed in EQ";
break;
case LINK_TRAINING_EQ_FAIL_EQ:
lt_result = "EQ failed";
break;
case LINK_TRAINING_LQA_FAIL:
lt_result = "LQA failed";
break;
default:
break;
}
/* Connectivity log: link training */
CONN_MSG_LT(link, "%sx%d %s VS=%d, PE=%d",
link_rate,
lt_settings.link_settings.lane_count,
(status == LINK_TRAINING_SUCCESS) ? "pass" :
((status == LINK_TRAINING_CR_FAIL) ? "CR failed" :
"EQ failed"),
lt_result,
lt_settings.lane_settings[0].VOLTAGE_SWING,
lt_settings.lane_settings[0].PRE_EMPHASIS);
@ -1115,6 +1151,7 @@ bool dp_hbr_verify_link_cap(
dp_cs_id,
cur);
if (skip_link_training)
success = true;
else {
@ -1279,7 +1316,10 @@ static bool decide_fallback_link_setting(
return false;
switch (training_result) {
case LINK_TRAINING_CR_FAIL:
case LINK_TRAINING_CR_FAIL_LANE0:
case LINK_TRAINING_CR_FAIL_LANE1:
case LINK_TRAINING_CR_FAIL_LANE23:
case LINK_TRAINING_LQA_FAIL:
{
if (!reached_minimum_link_rate
(current_link_setting->link_rate)) {
@ -1290,8 +1330,18 @@ static bool decide_fallback_link_setting(
(current_link_setting->lane_count)) {
current_link_setting->link_rate =
initial_link_settings.link_rate;
current_link_setting->lane_count =
reduce_lane_count(
if (training_result == LINK_TRAINING_CR_FAIL_LANE0)
return false;
else if (training_result == LINK_TRAINING_CR_FAIL_LANE1)
current_link_setting->lane_count =
LANE_COUNT_ONE;
else if (training_result ==
LINK_TRAINING_CR_FAIL_LANE23)
current_link_setting->lane_count =
LANE_COUNT_TWO;
else
current_link_setting->lane_count =
reduce_lane_count(
current_link_setting->lane_count);
} else {
return false;

1
drivers/gpu/drm/amd/display/dc/core/dc_link_hwss.c
View file

@ -279,6 +279,7 @@ void dp_retrain_link_dp_test(struct dc_link *link,
for (i = 0; i < MAX_PIPES; i++) {
if (pipes[i].stream != NULL &&
!pipes[i].top_pipe &&
pipes[i].stream->sink != NULL &&
pipes[i].stream->sink->link != NULL &&
pipes[i].stream_res.stream_enc != NULL &&

5
drivers/gpu/drm/amd/display/include/link_service_types.h
View file

@ -58,11 +58,14 @@ enum {
enum link_training_result {
LINK_TRAINING_SUCCESS,
LINK_TRAINING_CR_FAIL,
LINK_TRAINING_CR_FAIL_LANE0,
LINK_TRAINING_CR_FAIL_LANE1,
LINK_TRAINING_CR_FAIL_LANE23,
/* CR DONE bit is cleared during EQ step */
LINK_TRAINING_EQ_FAIL_CR,
/* other failure during EQ step */
LINK_TRAINING_EQ_FAIL_EQ,
LINK_TRAINING_LQA_FAIL,
};
struct link_training_settings {