[PATCH 08/10] drm/amd/display: Improve robustness of FIXED_VS link training at DP1 rates
Qingqing Zhuo
Qingqing.Zhuo at amd.com
Thu Mar 30 08:57:18 UTC 2023
From: Michael Strauss <michael.strauss at amd.com>
[WHY]
New sequence for transparent mode DP1.x link training was provided by LTTPR
vendor
[HOW]
Implement new FIXED_VS sequence, increase LT retry count to minimize
any potential intermittent lightup failures
Reviewed-by: Jun Lei <Jun.Lei at amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo at amd.com>
Signed-off-by: Michael Strauss <michael.strauss at amd.com>
---
drivers/gpu/drm/amd/display/dc/dc.h | 1 +
.../drm/amd/display/dc/dcn31/dcn31_resource.c | 2 +
.../gpu/drm/amd/display/dc/link/link_dpms.c | 8 +-
.../dc/link/protocols/link_dp_training.c | 5 +-
.../link_dp_training_fixed_vs_pe_retimer.c | 378 +++++++++++++++++-
.../link_dp_training_fixed_vs_pe_retimer.h | 5 +
6 files changed, 396 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/dc/dc.h b/drivers/gpu/drm/amd/display/dc/dc.h
index f51b9c265b51..190e6a2e1334 100644
--- a/drivers/gpu/drm/amd/display/dc/dc.h
+++ b/drivers/gpu/drm/amd/display/dc/dc.h
@@ -405,6 +405,7 @@ struct dc_config {
bool force_bios_enable_lttpr;
uint8_t force_bios_fixed_vs;
int sdpif_request_limit_words_per_umc;
+ bool use_old_fixed_vs_sequence;
bool disable_subvp_drr;
};
diff --git a/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_resource.c b/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_resource.c
index eaaa2e01f6d0..ff8cd5076434 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_resource.c
@@ -1965,6 +1965,8 @@ static bool dcn31_resource_construct(
dc->caps.color.mpc.ogam_rom_caps.hlg = 0;
dc->caps.color.mpc.ocsc = 1;
+ dc->config.use_old_fixed_vs_sequence = true;
+
/* Use pipe context based otg sync logic */
dc->config.use_pipe_ctx_sync_logic = true;
diff --git a/drivers/gpu/drm/amd/display/dc/link/link_dpms.c b/drivers/gpu/drm/amd/display/dc/link/link_dpms.c
index f6c5ee2d639b..027ad1f0144d 100644
--- a/drivers/gpu/drm/amd/display/dc/link/link_dpms.c
+++ b/drivers/gpu/drm/amd/display/dc/link/link_dpms.c
@@ -2035,6 +2035,12 @@ static enum dc_status enable_link_dp(struct dc_state *state,
uint32_t post_oui_delay = 30; // 30ms
/* Reduce link bandwidth between failed link training attempts. */
bool do_fallback = false;
+ int lt_attempts = LINK_TRAINING_ATTEMPTS;
+
+ // Increase retry count if attempting DP1.x on FIXED_VS link
+ if ((link->chip_caps & EXT_DISPLAY_PATH_CAPS__DP_FIXED_VS_EN) &&
+ link_dp_get_encoding_format(link_settings) == DP_8b_10b_ENCODING)
+ lt_attempts = 10;
// check for seamless boot
for (i = 0; i < state->stream_count; i++) {
@@ -2099,7 +2105,7 @@ static enum dc_status enable_link_dp(struct dc_state *state,
if (perform_link_training_with_retries(link_settings,
skip_video_pattern,
- LINK_TRAINING_ATTEMPTS,
+ lt_attempts,
pipe_ctx,
pipe_ctx->stream->signal,
do_fallback)) {
diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training.c b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training.c
index f301c9eaf2f9..70fc0ddf2d7e 100644
--- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training.c
+++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training.c
@@ -1496,7 +1496,10 @@ enum link_training_result dp_perform_link_training(
* Non-LT AUX transactions inside training mode.
*/
if ((link->chip_caps & EXT_DISPLAY_PATH_CAPS__DP_FIXED_VS_EN) && encoding == DP_8b_10b_ENCODING)
- status = dp_perform_fixed_vs_pe_training_sequence(link, link_res, <_settings);
+ if (link->dc->config.use_old_fixed_vs_sequence)
+ status = dp_perform_fixed_vs_pe_training_sequence_legacy(link, link_res, <_settings);
+ else
+ status = dp_perform_fixed_vs_pe_training_sequence(link, link_res, <_settings);
else if (encoding == DP_8b_10b_ENCODING)
status = dp_perform_8b_10b_link_training(link, link_res, <_settings);
else if (encoding == DP_128b_132b_ENCODING)
diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training_fixed_vs_pe_retimer.c b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training_fixed_vs_pe_retimer.c
index a4071d2959a0..5731c4b61f9f 100644
--- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training_fixed_vs_pe_retimer.c
+++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training_fixed_vs_pe_retimer.c
@@ -223,7 +223,7 @@ static enum link_training_result perform_fixed_vs_pe_nontransparent_training_seq
}
-enum link_training_result dp_perform_fixed_vs_pe_training_sequence(
+enum link_training_result dp_perform_fixed_vs_pe_training_sequence_legacy(
struct dc_link *link,
const struct link_resource *link_res,
struct link_training_settings *lt_settings)
@@ -577,3 +577,379 @@ enum link_training_result dp_perform_fixed_vs_pe_training_sequence(
return status;
}
+
+enum link_training_result dp_perform_fixed_vs_pe_training_sequence(
+ struct dc_link *link,
+ const struct link_resource *link_res,
+ struct link_training_settings *lt_settings)
+{
+ const uint8_t vendor_lttpr_write_data_reset[4] = {0x1, 0x50, 0x63, 0xFF};
+ const uint8_t offset = dp_parse_lttpr_repeater_count(
+ link->dpcd_caps.lttpr_caps.phy_repeater_cnt);
+ const uint8_t vendor_lttpr_write_data_intercept_en[4] = {0x1, 0x55, 0x63, 0x0};
+ const uint8_t vendor_lttpr_write_data_intercept_dis[4] = {0x1, 0x55, 0x63, 0x6E};
+ const uint8_t vendor_lttpr_write_data_adicora_eq1[4] = {0x1, 0x55, 0x63, 0x2E};
+ const uint8_t vendor_lttpr_write_data_adicora_eq2[4] = {0x1, 0x55, 0x63, 0x01};
+ const uint8_t vendor_lttpr_write_data_adicora_eq3[4] = {0x1, 0x55, 0x63, 0x68};
+ uint32_t pre_disable_intercept_delay_ms = link->dc->debug.fixed_vs_aux_delay_config_wa;
+ uint8_t vendor_lttpr_write_data_vs[4] = {0x1, 0x51, 0x63, 0x0};
+ uint8_t vendor_lttpr_write_data_pe[4] = {0x1, 0x52, 0x63, 0x0};
+
+ uint32_t vendor_lttpr_write_address = 0xF004F;
+ enum link_training_result status = LINK_TRAINING_SUCCESS;
+ uint8_t lane = 0;
+ union down_spread_ctrl downspread = {0};
+ union lane_count_set lane_count_set = {0};
+ uint8_t toggle_rate;
+ uint8_t rate;
+
+ /* Only 8b/10b is supported */
+ ASSERT(link_dp_get_encoding_format(<_settings->link_settings) ==
+ DP_8b_10b_ENCODING);
+
+ if (lt_settings->lttpr_mode == LTTPR_MODE_NON_TRANSPARENT) {
+ status = perform_fixed_vs_pe_nontransparent_training_sequence(link, link_res, lt_settings);
+ return status;
+ }
+
+ if (offset != 0xFF) {
+ vendor_lttpr_write_address +=
+ ((DP_REPEATER_CONFIGURATION_AND_STATUS_SIZE) * (offset - 1));
+
+ /* Certain display and cable configuration require extra delay */
+ if (offset > 2)
+ pre_disable_intercept_delay_ms = link->dc->debug.fixed_vs_aux_delay_config_wa * 2;
+ }
+
+ /* Vendor specific: Reset lane settings */
+ core_link_write_dpcd(
+ link,
+ vendor_lttpr_write_address,
+ &vendor_lttpr_write_data_reset[0],
+ sizeof(vendor_lttpr_write_data_reset));
+ core_link_write_dpcd(
+ link,
+ vendor_lttpr_write_address,
+ &vendor_lttpr_write_data_vs[0],
+ sizeof(vendor_lttpr_write_data_vs));
+ core_link_write_dpcd(
+ link,
+ vendor_lttpr_write_address,
+ &vendor_lttpr_write_data_pe[0],
+ sizeof(vendor_lttpr_write_data_pe));
+
+ /* Vendor specific: Enable intercept */
+ core_link_write_dpcd(
+ link,
+ vendor_lttpr_write_address,
+ &vendor_lttpr_write_data_intercept_en[0],
+ sizeof(vendor_lttpr_write_data_intercept_en));
+
+ /* 1. set link rate, lane count and spread. */
+
+ downspread.raw = (uint8_t)(lt_settings->link_settings.link_spread);
+
+ lane_count_set.bits.LANE_COUNT_SET =
+ lt_settings->link_settings.lane_count;
+
+ lane_count_set.bits.ENHANCED_FRAMING = lt_settings->enhanced_framing;
+ lane_count_set.bits.POST_LT_ADJ_REQ_GRANTED = 0;
+
+
+ if (lt_settings->pattern_for_eq < DP_TRAINING_PATTERN_SEQUENCE_4) {
+ lane_count_set.bits.POST_LT_ADJ_REQ_GRANTED =
+ link->dpcd_caps.max_ln_count.bits.POST_LT_ADJ_REQ_SUPPORTED;
+ }
+
+ core_link_write_dpcd(link, DP_DOWNSPREAD_CTRL,
+ &downspread.raw, sizeof(downspread));
+
+ core_link_write_dpcd(link, DP_LANE_COUNT_SET,
+ &lane_count_set.raw, 1);
+
+ rate = get_dpcd_link_rate(<_settings->link_settings);
+
+ /* Vendor specific: Toggle link rate */
+ toggle_rate = (rate == 0x6) ? 0xA : 0x6;
+
+ if (link->vendor_specific_lttpr_link_rate_wa == rate) {
+ core_link_write_dpcd(
+ link,
+ DP_LINK_BW_SET,
+ &toggle_rate,
+ 1);
+ }
+
+ link->vendor_specific_lttpr_link_rate_wa = rate;
+
+ core_link_write_dpcd(link, DP_LINK_BW_SET, &rate, 1);
+
+ DC_LOG_HW_LINK_TRAINING("%s\n %x rate = %x\n %x lane = %x framing = %x\n %x spread = %x\n",
+ __func__,
+ DP_LINK_BW_SET,
+ lt_settings->link_settings.link_rate,
+ DP_LANE_COUNT_SET,
+ lt_settings->link_settings.lane_count,
+ lt_settings->enhanced_framing,
+ DP_DOWNSPREAD_CTRL,
+ lt_settings->link_settings.link_spread);
+
+ /* 2. Perform link training */
+
+ /* Perform Clock Recovery Sequence */
+ if (status == LINK_TRAINING_SUCCESS) {
+ const uint8_t max_vendor_dpcd_retries = 10;
+ uint32_t retries_cr;
+ uint32_t retry_count;
+ uint32_t wait_time_microsec;
+ enum dc_lane_count lane_count = lt_settings->link_settings.lane_count;
+ union lane_status dpcd_lane_status[LANE_COUNT_DP_MAX];
+ union lane_align_status_updated dpcd_lane_status_updated;
+ union lane_adjust dpcd_lane_adjust[LANE_COUNT_DP_MAX] = {0};
+ enum dc_status dpcd_status = DC_OK;
+ uint8_t i = 0;
+
+ retries_cr = 0;
+ retry_count = 0;
+
+ memset(&dpcd_lane_status, '\0', sizeof(dpcd_lane_status));
+ memset(&dpcd_lane_status_updated, '\0',
+ sizeof(dpcd_lane_status_updated));
+
+ while ((retries_cr < LINK_TRAINING_MAX_RETRY_COUNT) &&
+ (retry_count < LINK_TRAINING_MAX_CR_RETRY)) {
+
+
+ /* 1. call HWSS to set lane settings */
+ dp_set_hw_lane_settings(
+ link,
+ link_res,
+ lt_settings,
+ 0);
+
+ /* 2. update DPCD of the receiver */
+ if (!retry_count) {
+ /* EPR #361076 - write as a 5-byte burst,
+ * but only for the 1-st iteration.
+ */
+ dpcd_set_lt_pattern_and_lane_settings(
+ link,
+ lt_settings,
+ lt_settings->pattern_for_cr,
+ 0);
+ /* Vendor specific: Disable intercept */
+ for (i = 0; i < max_vendor_dpcd_retries; i++) {
+ msleep(pre_disable_intercept_delay_ms);
+ dpcd_status = core_link_write_dpcd(
+ link,
+ vendor_lttpr_write_address,
+ &vendor_lttpr_write_data_intercept_dis[0],
+ sizeof(vendor_lttpr_write_data_intercept_dis));
+
+ if (dpcd_status == DC_OK)
+ break;
+
+ core_link_write_dpcd(
+ link,
+ vendor_lttpr_write_address,
+ &vendor_lttpr_write_data_intercept_en[0],
+ sizeof(vendor_lttpr_write_data_intercept_en));
+ }
+ } else {
+ vendor_lttpr_write_data_vs[3] = 0;
+ vendor_lttpr_write_data_pe[3] = 0;
+
+ for (lane = 0; lane < lane_count; lane++) {
+ vendor_lttpr_write_data_vs[3] |=
+ lt_settings->dpcd_lane_settings[lane].bits.VOLTAGE_SWING_SET << (2 * lane);
+ vendor_lttpr_write_data_pe[3] |=
+ lt_settings->dpcd_lane_settings[lane].bits.PRE_EMPHASIS_SET << (2 * lane);
+ }
+
+ /* Vendor specific: Update VS and PE to DPRX requested value */
+ core_link_write_dpcd(
+ link,
+ vendor_lttpr_write_address,
+ &vendor_lttpr_write_data_vs[0],
+ sizeof(vendor_lttpr_write_data_vs));
+ core_link_write_dpcd(
+ link,
+ vendor_lttpr_write_address,
+ &vendor_lttpr_write_data_pe[0],
+ sizeof(vendor_lttpr_write_data_pe));
+
+ dpcd_set_lane_settings(
+ link,
+ lt_settings,
+ 0);
+ }
+
+ /* 3. wait receiver to lock-on*/
+ wait_time_microsec = lt_settings->cr_pattern_time;
+
+ dp_wait_for_training_aux_rd_interval(
+ link,
+ wait_time_microsec);
+
+ /* 4. Read lane status and requested drive
+ * settings as set by the sink
+ */
+ dp_get_lane_status_and_lane_adjust(
+ link,
+ lt_settings,
+ dpcd_lane_status,
+ &dpcd_lane_status_updated,
+ dpcd_lane_adjust,
+ 0);
+
+ /* 5. check CR done*/
+ if (dp_is_cr_done(lane_count, dpcd_lane_status)) {
+ status = LINK_TRAINING_SUCCESS;
+ break;
+ }
+
+ /* 6. max VS reached*/
+ if (dp_is_max_vs_reached(lt_settings))
+ break;
+
+ /* 7. same lane settings */
+ /* Note: settings are the same for all lanes,
+ * so comparing first lane is sufficient
+ */
+ if (lt_settings->dpcd_lane_settings[0].bits.VOLTAGE_SWING_SET ==
+ dpcd_lane_adjust[0].bits.VOLTAGE_SWING_LANE)
+ retries_cr++;
+ else
+ retries_cr = 0;
+
+ /* 8. update VS/PE/PC2 in lt_settings*/
+ dp_decide_lane_settings(lt_settings, dpcd_lane_adjust,
+ lt_settings->hw_lane_settings, lt_settings->dpcd_lane_settings);
+ retry_count++;
+ }
+
+ if (retry_count >= LINK_TRAINING_MAX_CR_RETRY) {
+ ASSERT(0);
+ DC_LOG_ERROR("%s: Link Training Error, could not get CR after %d tries. Possibly voltage swing issue",
+ __func__,
+ LINK_TRAINING_MAX_CR_RETRY);
+
+ }
+
+ status = dp_get_cr_failure(lane_count, dpcd_lane_status);
+ }
+
+ /* Perform Channel EQ Sequence */
+ if (status == LINK_TRAINING_SUCCESS) {
+ enum dc_dp_training_pattern tr_pattern;
+ uint32_t retries_ch_eq;
+ uint32_t wait_time_microsec;
+ enum dc_lane_count lane_count = lt_settings->link_settings.lane_count;
+ union lane_align_status_updated dpcd_lane_status_updated = {0};
+ union lane_status dpcd_lane_status[LANE_COUNT_DP_MAX] = {0};
+ union lane_adjust dpcd_lane_adjust[LANE_COUNT_DP_MAX] = {0};
+
+ core_link_write_dpcd(
+ link,
+ vendor_lttpr_write_address,
+ &vendor_lttpr_write_data_adicora_eq1[0],
+ sizeof(vendor_lttpr_write_data_adicora_eq1));
+ core_link_write_dpcd(
+ link,
+ vendor_lttpr_write_address,
+ &vendor_lttpr_write_data_adicora_eq2[0],
+ sizeof(vendor_lttpr_write_data_adicora_eq2));
+
+ /* Note: also check that TPS4 is a supported feature*/
+ tr_pattern = lt_settings->pattern_for_eq;
+
+ dp_set_hw_training_pattern(link, link_res, tr_pattern, 0);
+
+ status = LINK_TRAINING_EQ_FAIL_EQ;
+
+ for (retries_ch_eq = 0; retries_ch_eq <= LINK_TRAINING_MAX_RETRY_COUNT;
+ retries_ch_eq++) {
+
+ dp_set_hw_lane_settings(link, link_res, lt_settings, 0);
+
+ vendor_lttpr_write_data_vs[3] = 0;
+ vendor_lttpr_write_data_pe[3] = 0;
+
+ for (lane = 0; lane < lane_count; lane++) {
+ vendor_lttpr_write_data_vs[3] |=
+ lt_settings->dpcd_lane_settings[lane].bits.VOLTAGE_SWING_SET << (2 * lane);
+ vendor_lttpr_write_data_pe[3] |=
+ lt_settings->dpcd_lane_settings[lane].bits.PRE_EMPHASIS_SET << (2 * lane);
+ }
+
+ /* Vendor specific: Update VS and PE to DPRX requested value */
+ core_link_write_dpcd(
+ link,
+ vendor_lttpr_write_address,
+ &vendor_lttpr_write_data_vs[0],
+ sizeof(vendor_lttpr_write_data_vs));
+ core_link_write_dpcd(
+ link,
+ vendor_lttpr_write_address,
+ &vendor_lttpr_write_data_pe[0],
+ sizeof(vendor_lttpr_write_data_pe));
+
+ /* 2. update DPCD*/
+ if (!retries_ch_eq) {
+ /* EPR #361076 - write as a 5-byte burst,
+ * but only for the 1-st iteration
+ */
+
+ dpcd_set_lt_pattern_and_lane_settings(
+ link,
+ lt_settings,
+ tr_pattern, 0);
+
+ core_link_write_dpcd(
+ link,
+ vendor_lttpr_write_address,
+ &vendor_lttpr_write_data_adicora_eq3[0],
+ sizeof(vendor_lttpr_write_data_adicora_eq3));
+ } else
+ dpcd_set_lane_settings(link, lt_settings, 0);
+
+ /* 3. wait for receiver to lock-on*/
+ wait_time_microsec = lt_settings->eq_pattern_time;
+
+ dp_wait_for_training_aux_rd_interval(
+ link,
+ wait_time_microsec);
+
+ /* 4. Read lane status and requested
+ * drive settings as set by the sink
+ */
+ dp_get_lane_status_and_lane_adjust(
+ link,
+ lt_settings,
+ dpcd_lane_status,
+ &dpcd_lane_status_updated,
+ dpcd_lane_adjust,
+ 0);
+
+ /* 5. check CR done*/
+ if (!dp_is_cr_done(lane_count, dpcd_lane_status)) {
+ status = LINK_TRAINING_EQ_FAIL_CR;
+ break;
+ }
+
+ /* 6. check CHEQ done*/
+ if (dp_is_ch_eq_done(lane_count, dpcd_lane_status) &&
+ dp_is_symbol_locked(lane_count, dpcd_lane_status) &&
+ dp_is_interlane_aligned(dpcd_lane_status_updated)) {
+ status = LINK_TRAINING_SUCCESS;
+ break;
+ }
+
+ /* 7. update VS/PE/PC2 in lt_settings*/
+ dp_decide_lane_settings(lt_settings, dpcd_lane_adjust,
+ lt_settings->hw_lane_settings, lt_settings->dpcd_lane_settings);
+ }
+ }
+
+ return status;
+}
diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training_fixed_vs_pe_retimer.h b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training_fixed_vs_pe_retimer.h
index e61970e27661..c0d6ea329504 100644
--- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training_fixed_vs_pe_retimer.h
+++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training_fixed_vs_pe_retimer.h
@@ -28,6 +28,11 @@
#define __DC_LINK_DP_FIXED_VS_PE_RETIMER_H__
#include "link_dp_training.h"
+enum link_training_result dp_perform_fixed_vs_pe_training_sequence_legacy(
+ struct dc_link *link,
+ const struct link_resource *link_res,
+ struct link_training_settings *lt_settings);
+
enum link_training_result dp_perform_fixed_vs_pe_training_sequence(
struct dc_link *link,
const struct link_resource *link_res,
--
2.34.1
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