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-rw-r--r--drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training.c1732
1 files changed, 1732 insertions, 0 deletions
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
new file mode 100644
index 000000000..5a0b04518
--- /dev/null
+++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training.c
@@ -0,0 +1,1732 @@
+/*
+ * Copyright 2022 Advanced Micro Devices, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Authors: AMD
+ *
+ */
+
+/* FILE POLICY AND INTENDED USAGE:
+ * This file implements all generic dp link training helper functions and top
+ * level generic training sequence. All variations of dp link training sequence
+ * should be called inside the top level training functions in this file to
+ * ensure the integrity of our overall training procedure across different types
+ * of link encoding and back end hardware.
+ */
+#include "link_dp_training.h"
+#include "link_dp_training_8b_10b.h"
+#include "link_dp_training_128b_132b.h"
+#include "link_dp_training_auxless.h"
+#include "link_dp_training_dpia.h"
+#include "link_dp_training_fixed_vs_pe_retimer.h"
+#include "link_dpcd.h"
+#include "link/accessories/link_dp_trace.h"
+#include "link_dp_phy.h"
+#include "link_dp_capability.h"
+#include "link_edp_panel_control.h"
+#include "link/link_detection.h"
+#include "link/link_validation.h"
+#include "atomfirmware.h"
+#include "link_enc_cfg.h"
+#include "resource.h"
+#include "dm_helpers.h"
+
+#define DC_LOGGER \
+ link->ctx->logger
+
+#define POST_LT_ADJ_REQ_LIMIT 6
+#define POST_LT_ADJ_REQ_TIMEOUT 200
+#define LINK_TRAINING_RETRY_DELAY 50 /* ms */
+
+void dp_log_training_result(
+ struct dc_link *link,
+ const struct link_training_settings *lt_settings,
+ enum link_training_result status)
+{
+ char *link_rate = "Unknown";
+ char *lt_result = "Unknown";
+ char *lt_spread = "Disabled";
+
+ switch (lt_settings->link_settings.link_rate) {
+ case LINK_RATE_LOW:
+ link_rate = "RBR";
+ break;
+ case LINK_RATE_RATE_2:
+ link_rate = "R2";
+ break;
+ case LINK_RATE_RATE_3:
+ link_rate = "R3";
+ break;
+ case LINK_RATE_HIGH:
+ link_rate = "HBR";
+ break;
+ case LINK_RATE_RBR2:
+ link_rate = "RBR2";
+ break;
+ case LINK_RATE_RATE_6:
+ link_rate = "R6";
+ break;
+ case LINK_RATE_HIGH2:
+ link_rate = "HBR2";
+ break;
+ case LINK_RATE_RATE_8:
+ link_rate = "R8";
+ break;
+ case LINK_RATE_HIGH3:
+ link_rate = "HBR3";
+ break;
+ case LINK_RATE_UHBR10:
+ link_rate = "UHBR10";
+ break;
+ case LINK_RATE_UHBR13_5:
+ link_rate = "UHBR13.5";
+ break;
+ case LINK_RATE_UHBR20:
+ link_rate = "UHBR20";
+ break;
+ default:
+ 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_CR_PARTIAL:
+ lt_result = "CR failed in EQ partially";
+ break;
+ case LINK_TRAINING_EQ_FAIL_EQ:
+ lt_result = "EQ failed";
+ break;
+ case LINK_TRAINING_LQA_FAIL:
+ lt_result = "LQA failed";
+ break;
+ case LINK_TRAINING_LINK_LOSS:
+ lt_result = "Link loss";
+ break;
+ case DP_128b_132b_LT_FAILED:
+ lt_result = "LT_FAILED received";
+ break;
+ case DP_128b_132b_MAX_LOOP_COUNT_REACHED:
+ lt_result = "max loop count reached";
+ break;
+ case DP_128b_132b_CHANNEL_EQ_DONE_TIMEOUT:
+ lt_result = "channel EQ timeout";
+ break;
+ case DP_128b_132b_CDS_DONE_TIMEOUT:
+ lt_result = "CDS timeout";
+ break;
+ default:
+ break;
+ }
+
+ switch (lt_settings->link_settings.link_spread) {
+ case LINK_SPREAD_DISABLED:
+ lt_spread = "Disabled";
+ break;
+ case LINK_SPREAD_05_DOWNSPREAD_30KHZ:
+ lt_spread = "0.5% 30KHz";
+ break;
+ case LINK_SPREAD_05_DOWNSPREAD_33KHZ:
+ lt_spread = "0.5% 33KHz";
+ break;
+ default:
+ break;
+ }
+
+ /* Connectivity log: link training */
+
+ /* TODO - DP2.0 Log: add connectivity log for FFE PRESET */
+
+ CONN_MSG_LT(link, "%sx%d %s VS=%d, PE=%d, DS=%s",
+ link_rate,
+ lt_settings->link_settings.lane_count,
+ lt_result,
+ lt_settings->hw_lane_settings[0].VOLTAGE_SWING,
+ lt_settings->hw_lane_settings[0].PRE_EMPHASIS,
+ lt_spread);
+}
+
+uint8_t dp_initialize_scrambling_data_symbols(
+ struct dc_link *link,
+ enum dc_dp_training_pattern pattern)
+{
+ uint8_t disable_scrabled_data_symbols = 0;
+
+ switch (pattern) {
+ case DP_TRAINING_PATTERN_SEQUENCE_1:
+ case DP_TRAINING_PATTERN_SEQUENCE_2:
+ case DP_TRAINING_PATTERN_SEQUENCE_3:
+ disable_scrabled_data_symbols = 1;
+ break;
+ case DP_TRAINING_PATTERN_SEQUENCE_4:
+ case DP_128b_132b_TPS1:
+ case DP_128b_132b_TPS2:
+ disable_scrabled_data_symbols = 0;
+ break;
+ default:
+ ASSERT(0);
+ DC_LOG_HW_LINK_TRAINING("%s: Invalid HW Training pattern: %d\n",
+ __func__, pattern);
+ break;
+ }
+ return disable_scrabled_data_symbols;
+}
+
+enum dpcd_training_patterns
+ dp_training_pattern_to_dpcd_training_pattern(
+ struct dc_link *link,
+ enum dc_dp_training_pattern pattern)
+{
+ enum dpcd_training_patterns dpcd_tr_pattern =
+ DPCD_TRAINING_PATTERN_VIDEOIDLE;
+
+ switch (pattern) {
+ case DP_TRAINING_PATTERN_SEQUENCE_1:
+ DC_LOG_HW_LINK_TRAINING("%s: Using DP training pattern TPS1\n", __func__);
+ dpcd_tr_pattern = DPCD_TRAINING_PATTERN_1;
+ break;
+ case DP_TRAINING_PATTERN_SEQUENCE_2:
+ DC_LOG_HW_LINK_TRAINING("%s: Using DP training pattern TPS2\n", __func__);
+ dpcd_tr_pattern = DPCD_TRAINING_PATTERN_2;
+ break;
+ case DP_TRAINING_PATTERN_SEQUENCE_3:
+ DC_LOG_HW_LINK_TRAINING("%s: Using DP training pattern TPS3\n", __func__);
+ dpcd_tr_pattern = DPCD_TRAINING_PATTERN_3;
+ break;
+ case DP_TRAINING_PATTERN_SEQUENCE_4:
+ DC_LOG_HW_LINK_TRAINING("%s: Using DP training pattern TPS4\n", __func__);
+ dpcd_tr_pattern = DPCD_TRAINING_PATTERN_4;
+ break;
+ case DP_128b_132b_TPS1:
+ DC_LOG_HW_LINK_TRAINING("%s: Using DP 128b/132b training pattern TPS1\n", __func__);
+ dpcd_tr_pattern = DPCD_128b_132b_TPS1;
+ break;
+ case DP_128b_132b_TPS2:
+ DC_LOG_HW_LINK_TRAINING("%s: Using DP 128b/132b training pattern TPS2\n", __func__);
+ dpcd_tr_pattern = DPCD_128b_132b_TPS2;
+ break;
+ case DP_128b_132b_TPS2_CDS:
+ DC_LOG_HW_LINK_TRAINING("%s: Using DP 128b/132b training pattern TPS2 CDS\n",
+ __func__);
+ dpcd_tr_pattern = DPCD_128b_132b_TPS2_CDS;
+ break;
+ case DP_TRAINING_PATTERN_VIDEOIDLE:
+ DC_LOG_HW_LINK_TRAINING("%s: Using DP training pattern videoidle\n", __func__);
+ dpcd_tr_pattern = DPCD_TRAINING_PATTERN_VIDEOIDLE;
+ break;
+ default:
+ ASSERT(0);
+ DC_LOG_HW_LINK_TRAINING("%s: Invalid HW Training pattern: %d\n",
+ __func__, pattern);
+ break;
+ }
+
+ return dpcd_tr_pattern;
+}
+
+uint8_t dp_get_nibble_at_index(const uint8_t *buf,
+ uint32_t index)
+{
+ uint8_t nibble;
+ nibble = buf[index / 2];
+
+ if (index % 2)
+ nibble >>= 4;
+ else
+ nibble &= 0x0F;
+
+ return nibble;
+}
+
+void dp_wait_for_training_aux_rd_interval(
+ struct dc_link *link,
+ uint32_t wait_in_micro_secs)
+{
+ fsleep(wait_in_micro_secs);
+
+ DC_LOG_HW_LINK_TRAINING("%s:\n wait = %d\n",
+ __func__,
+ wait_in_micro_secs);
+}
+
+/* maximum pre emphasis level allowed for each voltage swing level*/
+static const enum dc_pre_emphasis voltage_swing_to_pre_emphasis[] = {
+ PRE_EMPHASIS_LEVEL3,
+ PRE_EMPHASIS_LEVEL2,
+ PRE_EMPHASIS_LEVEL1,
+ PRE_EMPHASIS_DISABLED };
+
+static enum dc_pre_emphasis get_max_pre_emphasis_for_voltage_swing(
+ enum dc_voltage_swing voltage)
+{
+ enum dc_pre_emphasis pre_emphasis;
+ pre_emphasis = PRE_EMPHASIS_MAX_LEVEL;
+
+ if (voltage <= VOLTAGE_SWING_MAX_LEVEL)
+ pre_emphasis = voltage_swing_to_pre_emphasis[voltage];
+
+ return pre_emphasis;
+
+}
+
+static void maximize_lane_settings(const struct link_training_settings *lt_settings,
+ struct dc_lane_settings lane_settings[LANE_COUNT_DP_MAX])
+{
+ uint32_t lane;
+ struct dc_lane_settings max_requested;
+
+ max_requested.VOLTAGE_SWING = lane_settings[0].VOLTAGE_SWING;
+ max_requested.PRE_EMPHASIS = lane_settings[0].PRE_EMPHASIS;
+ max_requested.FFE_PRESET = lane_settings[0].FFE_PRESET;
+
+ /* Determine what the maximum of the requested settings are*/
+ for (lane = 1; lane < lt_settings->link_settings.lane_count; lane++) {
+ if (lane_settings[lane].VOLTAGE_SWING > max_requested.VOLTAGE_SWING)
+ max_requested.VOLTAGE_SWING = lane_settings[lane].VOLTAGE_SWING;
+
+ if (lane_settings[lane].PRE_EMPHASIS > max_requested.PRE_EMPHASIS)
+ max_requested.PRE_EMPHASIS = lane_settings[lane].PRE_EMPHASIS;
+ if (lane_settings[lane].FFE_PRESET.settings.level >
+ max_requested.FFE_PRESET.settings.level)
+ max_requested.FFE_PRESET.settings.level =
+ lane_settings[lane].FFE_PRESET.settings.level;
+ }
+
+ /* make sure the requested settings are
+ * not higher than maximum settings*/
+ if (max_requested.VOLTAGE_SWING > VOLTAGE_SWING_MAX_LEVEL)
+ max_requested.VOLTAGE_SWING = VOLTAGE_SWING_MAX_LEVEL;
+
+ if (max_requested.PRE_EMPHASIS > PRE_EMPHASIS_MAX_LEVEL)
+ max_requested.PRE_EMPHASIS = PRE_EMPHASIS_MAX_LEVEL;
+ if (max_requested.FFE_PRESET.settings.level > DP_FFE_PRESET_MAX_LEVEL)
+ max_requested.FFE_PRESET.settings.level = DP_FFE_PRESET_MAX_LEVEL;
+
+ /* make sure the pre-emphasis matches the voltage swing*/
+ if (max_requested.PRE_EMPHASIS >
+ get_max_pre_emphasis_for_voltage_swing(
+ max_requested.VOLTAGE_SWING))
+ max_requested.PRE_EMPHASIS =
+ get_max_pre_emphasis_for_voltage_swing(
+ max_requested.VOLTAGE_SWING);
+
+ for (lane = 0; lane < LANE_COUNT_DP_MAX; lane++) {
+ lane_settings[lane].VOLTAGE_SWING = max_requested.VOLTAGE_SWING;
+ lane_settings[lane].PRE_EMPHASIS = max_requested.PRE_EMPHASIS;
+ lane_settings[lane].FFE_PRESET = max_requested.FFE_PRESET;
+ }
+}
+
+void dp_hw_to_dpcd_lane_settings(
+ const struct link_training_settings *lt_settings,
+ const struct dc_lane_settings hw_lane_settings[LANE_COUNT_DP_MAX],
+ union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX])
+{
+ uint8_t lane = 0;
+
+ for (lane = 0; lane < LANE_COUNT_DP_MAX; lane++) {
+ if (link_dp_get_encoding_format(&lt_settings->link_settings) ==
+ DP_8b_10b_ENCODING) {
+ dpcd_lane_settings[lane].bits.VOLTAGE_SWING_SET =
+ (uint8_t)(hw_lane_settings[lane].VOLTAGE_SWING);
+ dpcd_lane_settings[lane].bits.PRE_EMPHASIS_SET =
+ (uint8_t)(hw_lane_settings[lane].PRE_EMPHASIS);
+ dpcd_lane_settings[lane].bits.MAX_SWING_REACHED =
+ (hw_lane_settings[lane].VOLTAGE_SWING ==
+ VOLTAGE_SWING_MAX_LEVEL ? 1 : 0);
+ dpcd_lane_settings[lane].bits.MAX_PRE_EMPHASIS_REACHED =
+ (hw_lane_settings[lane].PRE_EMPHASIS ==
+ PRE_EMPHASIS_MAX_LEVEL ? 1 : 0);
+ } else if (link_dp_get_encoding_format(&lt_settings->link_settings) ==
+ DP_128b_132b_ENCODING) {
+ dpcd_lane_settings[lane].tx_ffe.PRESET_VALUE =
+ hw_lane_settings[lane].FFE_PRESET.settings.level;
+ }
+ }
+}
+
+uint8_t get_dpcd_link_rate(const struct dc_link_settings *link_settings)
+{
+ uint8_t link_rate = 0;
+ enum dp_link_encoding encoding = link_dp_get_encoding_format(link_settings);
+
+ if (encoding == DP_128b_132b_ENCODING)
+ switch (link_settings->link_rate) {
+ case LINK_RATE_UHBR10:
+ link_rate = 0x1;
+ break;
+ case LINK_RATE_UHBR20:
+ link_rate = 0x2;
+ break;
+ case LINK_RATE_UHBR13_5:
+ link_rate = 0x4;
+ break;
+ default:
+ link_rate = 0;
+ break;
+ }
+ else if (encoding == DP_8b_10b_ENCODING)
+ link_rate = (uint8_t) link_settings->link_rate;
+ else
+ link_rate = 0;
+
+ return link_rate;
+}
+
+/* Only used for channel equalization */
+uint32_t dp_translate_training_aux_read_interval(uint32_t dpcd_aux_read_interval)
+{
+ unsigned int aux_rd_interval_us = 400;
+
+ switch (dpcd_aux_read_interval) {
+ case 0x01:
+ aux_rd_interval_us = 4000;
+ break;
+ case 0x02:
+ aux_rd_interval_us = 8000;
+ break;
+ case 0x03:
+ aux_rd_interval_us = 12000;
+ break;
+ case 0x04:
+ aux_rd_interval_us = 16000;
+ break;
+ case 0x05:
+ aux_rd_interval_us = 32000;
+ break;
+ case 0x06:
+ aux_rd_interval_us = 64000;
+ break;
+ default:
+ break;
+ }
+
+ return aux_rd_interval_us;
+}
+
+enum link_training_result dp_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;
+}
+
+bool is_repeater(const struct link_training_settings *lt_settings, uint32_t offset)
+{
+ return (lt_settings->lttpr_mode == LTTPR_MODE_NON_TRANSPARENT) && (offset != 0);
+}
+
+bool dp_is_max_vs_reached(
+ const struct link_training_settings *lt_settings)
+{
+ uint32_t lane;
+ for (lane = 0; lane <
+ (uint32_t)(lt_settings->link_settings.lane_count);
+ lane++) {
+ if (lt_settings->dpcd_lane_settings[lane].bits.VOLTAGE_SWING_SET
+ == VOLTAGE_SWING_MAX_LEVEL)
+ return true;
+ }
+ return false;
+
+}
+
+bool dp_is_cr_done(enum dc_lane_count ln_count,
+ union lane_status *dpcd_lane_status)
+{
+ bool done = true;
+ uint32_t lane;
+ /*LANEx_CR_DONE bits All 1's?*/
+ for (lane = 0; lane < (uint32_t)(ln_count); lane++) {
+ if (!dpcd_lane_status[lane].bits.CR_DONE_0)
+ done = false;
+ }
+ return done;
+
+}
+
+bool dp_is_ch_eq_done(enum dc_lane_count ln_count,
+ union lane_status *dpcd_lane_status)
+{
+ bool done = true;
+ uint32_t lane;
+ for (lane = 0; lane < (uint32_t)(ln_count); lane++)
+ if (!dpcd_lane_status[lane].bits.CHANNEL_EQ_DONE_0)
+ done = false;
+ return done;
+}
+
+bool dp_is_symbol_locked(enum dc_lane_count ln_count,
+ union lane_status *dpcd_lane_status)
+{
+ bool locked = true;
+ uint32_t lane;
+ for (lane = 0; lane < (uint32_t)(ln_count); lane++)
+ if (!dpcd_lane_status[lane].bits.SYMBOL_LOCKED_0)
+ locked = false;
+ return locked;
+}
+
+bool dp_is_interlane_aligned(union lane_align_status_updated align_status)
+{
+ return align_status.bits.INTERLANE_ALIGN_DONE == 1;
+}
+
+enum link_training_result dp_check_link_loss_status(
+ struct dc_link *link,
+ const struct link_training_settings *link_training_setting)
+{
+ enum link_training_result status = LINK_TRAINING_SUCCESS;
+ union lane_status lane_status;
+ uint8_t dpcd_buf[6] = {0};
+ uint32_t lane;
+
+ core_link_read_dpcd(
+ link,
+ DP_SINK_COUNT,
+ (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 = dp_get_nibble_at_index(&dpcd_buf[2], 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;
+}
+
+enum dc_status dp_get_lane_status_and_lane_adjust(
+ struct dc_link *link,
+ const struct link_training_settings *link_training_setting,
+ union lane_status ln_status[LANE_COUNT_DP_MAX],
+ union lane_align_status_updated *ln_align,
+ union lane_adjust ln_adjust[LANE_COUNT_DP_MAX],
+ uint32_t offset)
+{
+ unsigned int lane01_status_address = DP_LANE0_1_STATUS;
+ uint8_t lane_adjust_offset = 4;
+ unsigned int lane01_adjust_address;
+ uint8_t dpcd_buf[6] = {0};
+ uint32_t lane;
+ enum dc_status status;
+
+ if (is_repeater(link_training_setting, offset)) {
+ lane01_status_address =
+ DP_LANE0_1_STATUS_PHY_REPEATER1 +
+ ((DP_REPEATER_CONFIGURATION_AND_STATUS_SIZE) * (offset - 1));
+ lane_adjust_offset = 3;
+ }
+
+ status = core_link_read_dpcd(
+ link,
+ lane01_status_address,
+ (uint8_t *)(dpcd_buf),
+ sizeof(dpcd_buf));
+
+ if (status != DC_OK) {
+ DC_LOG_HW_LINK_TRAINING("%s:\n Failed to read from address 0x%X,"
+ " keep current lane status and lane adjust unchanged",
+ __func__,
+ lane01_status_address);
+ return status;
+ }
+
+ for (lane = 0; lane <
+ (uint32_t)(link_training_setting->link_settings.lane_count);
+ lane++) {
+
+ ln_status[lane].raw =
+ dp_get_nibble_at_index(&dpcd_buf[0], lane);
+ ln_adjust[lane].raw =
+ dp_get_nibble_at_index(&dpcd_buf[lane_adjust_offset], lane);
+ }
+
+ ln_align->raw = dpcd_buf[2];
+
+ if (is_repeater(link_training_setting, offset)) {
+ DC_LOG_HW_LINK_TRAINING("%s:\n LTTPR Repeater ID: %d\n"
+ " 0x%X Lane01Status = %x\n 0x%X Lane23Status = %x\n ",
+ __func__,
+ offset,
+ lane01_status_address, dpcd_buf[0],
+ lane01_status_address + 1, dpcd_buf[1]);
+
+ lane01_adjust_address = DP_ADJUST_REQUEST_LANE0_1_PHY_REPEATER1 +
+ ((DP_REPEATER_CONFIGURATION_AND_STATUS_SIZE) * (offset - 1));
+
+ DC_LOG_HW_LINK_TRAINING("%s:\n LTTPR Repeater ID: %d\n"
+ " 0x%X Lane01AdjustRequest = %x\n 0x%X Lane23AdjustRequest = %x\n",
+ __func__,
+ offset,
+ lane01_adjust_address,
+ dpcd_buf[lane_adjust_offset],
+ lane01_adjust_address + 1,
+ dpcd_buf[lane_adjust_offset + 1]);
+ } else {
+ DC_LOG_HW_LINK_TRAINING("%s:\n 0x%X Lane01Status = %x\n 0x%X Lane23Status = %x\n ",
+ __func__,
+ lane01_status_address, dpcd_buf[0],
+ lane01_status_address + 1, dpcd_buf[1]);
+
+ lane01_adjust_address = DP_ADJUST_REQUEST_LANE0_1;
+
+ DC_LOG_HW_LINK_TRAINING("%s:\n 0x%X Lane01AdjustRequest = %x\n 0x%X Lane23AdjustRequest = %x\n",
+ __func__,
+ lane01_adjust_address,
+ dpcd_buf[lane_adjust_offset],
+ lane01_adjust_address + 1,
+ dpcd_buf[lane_adjust_offset + 1]);
+ }
+
+ return status;
+}
+
+static void override_lane_settings(const struct link_training_settings *lt_settings,
+ struct dc_lane_settings lane_settings[LANE_COUNT_DP_MAX])
+{
+ uint32_t lane;
+
+ if (lt_settings->voltage_swing == NULL &&
+ lt_settings->pre_emphasis == NULL &&
+ lt_settings->ffe_preset == NULL &&
+ lt_settings->post_cursor2 == NULL)
+
+ return;
+
+ for (lane = 0; lane < LANE_COUNT_DP_MAX; lane++) {
+ if (lt_settings->voltage_swing)
+ lane_settings[lane].VOLTAGE_SWING = *lt_settings->voltage_swing;
+ if (lt_settings->pre_emphasis)
+ lane_settings[lane].PRE_EMPHASIS = *lt_settings->pre_emphasis;
+ if (lt_settings->post_cursor2)
+ lane_settings[lane].POST_CURSOR2 = *lt_settings->post_cursor2;
+ if (lt_settings->ffe_preset)
+ lane_settings[lane].FFE_PRESET = *lt_settings->ffe_preset;
+ }
+}
+
+void dp_get_lttpr_mode_override(struct dc_link *link, enum lttpr_mode *override)
+{
+ if (!dp_is_lttpr_present(link))
+ return;
+
+ if (link->dc->debug.lttpr_mode_override == LTTPR_MODE_TRANSPARENT) {
+ *override = LTTPR_MODE_TRANSPARENT;
+ } else if (link->dc->debug.lttpr_mode_override == LTTPR_MODE_NON_TRANSPARENT) {
+ *override = LTTPR_MODE_NON_TRANSPARENT;
+ } else if (link->dc->debug.lttpr_mode_override == LTTPR_MODE_NON_LTTPR) {
+ *override = LTTPR_MODE_NON_LTTPR;
+ }
+ DC_LOG_DC("lttpr_mode_override chose LTTPR_MODE = %d\n", (uint8_t)(*override));
+}
+
+void override_training_settings(
+ struct dc_link *link,
+ const struct dc_link_training_overrides *overrides,
+ struct link_training_settings *lt_settings)
+{
+ uint32_t lane;
+
+ /* Override link spread */
+ if (!link->dp_ss_off && overrides->downspread != NULL)
+ lt_settings->link_settings.link_spread = *overrides->downspread ?
+ LINK_SPREAD_05_DOWNSPREAD_30KHZ
+ : LINK_SPREAD_DISABLED;
+
+ /* Override lane settings */
+ if (overrides->voltage_swing != NULL)
+ lt_settings->voltage_swing = overrides->voltage_swing;
+ if (overrides->pre_emphasis != NULL)
+ lt_settings->pre_emphasis = overrides->pre_emphasis;
+ if (overrides->post_cursor2 != NULL)
+ lt_settings->post_cursor2 = overrides->post_cursor2;
+ if (overrides->ffe_preset != NULL)
+ lt_settings->ffe_preset = overrides->ffe_preset;
+ /* Override HW lane settings with BIOS forced values if present */
+ if ((link->chip_caps & EXT_DISPLAY_PATH_CAPS__DP_FIXED_VS_EN) &&
+ lt_settings->lttpr_mode == LTTPR_MODE_TRANSPARENT) {
+ lt_settings->voltage_swing = &link->bios_forced_drive_settings.VOLTAGE_SWING;
+ lt_settings->pre_emphasis = &link->bios_forced_drive_settings.PRE_EMPHASIS;
+ lt_settings->always_match_dpcd_with_hw_lane_settings = false;
+ }
+ for (lane = 0; lane < LANE_COUNT_DP_MAX; lane++) {
+ lt_settings->hw_lane_settings[lane].VOLTAGE_SWING =
+ lt_settings->voltage_swing != NULL ?
+ *lt_settings->voltage_swing :
+ VOLTAGE_SWING_LEVEL0;
+ lt_settings->hw_lane_settings[lane].PRE_EMPHASIS =
+ lt_settings->pre_emphasis != NULL ?
+ *lt_settings->pre_emphasis
+ : PRE_EMPHASIS_DISABLED;
+ lt_settings->hw_lane_settings[lane].POST_CURSOR2 =
+ lt_settings->post_cursor2 != NULL ?
+ *lt_settings->post_cursor2
+ : POST_CURSOR2_DISABLED;
+ }
+
+ if (lt_settings->always_match_dpcd_with_hw_lane_settings)
+ dp_hw_to_dpcd_lane_settings(lt_settings,
+ lt_settings->hw_lane_settings, lt_settings->dpcd_lane_settings);
+
+ /* Override training timings */
+ if (overrides->cr_pattern_time != NULL)
+ lt_settings->cr_pattern_time = *overrides->cr_pattern_time;
+ if (overrides->eq_pattern_time != NULL)
+ lt_settings->eq_pattern_time = *overrides->eq_pattern_time;
+ if (overrides->pattern_for_cr != NULL)
+ lt_settings->pattern_for_cr = *overrides->pattern_for_cr;
+ if (overrides->pattern_for_eq != NULL)
+ lt_settings->pattern_for_eq = *overrides->pattern_for_eq;
+ if (overrides->enhanced_framing != NULL)
+ lt_settings->enhanced_framing = *overrides->enhanced_framing;
+ if (link->preferred_training_settings.fec_enable != NULL)
+ lt_settings->should_set_fec_ready = *link->preferred_training_settings.fec_enable;
+
+ /* Check DP tunnel LTTPR mode debug option. */
+ if (link->ep_type == DISPLAY_ENDPOINT_USB4_DPIA && link->dc->debug.dpia_debug.bits.force_non_lttpr)
+ lt_settings->lttpr_mode = LTTPR_MODE_NON_LTTPR;
+
+ dp_get_lttpr_mode_override(link, &lt_settings->lttpr_mode);
+
+}
+
+enum dc_dp_training_pattern decide_cr_training_pattern(
+ const struct dc_link_settings *link_settings)
+{
+ switch (link_dp_get_encoding_format(link_settings)) {
+ case DP_8b_10b_ENCODING:
+ default:
+ return DP_TRAINING_PATTERN_SEQUENCE_1;
+ case DP_128b_132b_ENCODING:
+ return DP_128b_132b_TPS1;
+ }
+}
+
+enum dc_dp_training_pattern decide_eq_training_pattern(struct dc_link *link,
+ const struct dc_link_settings *link_settings)
+{
+ struct link_encoder *link_enc;
+ struct encoder_feature_support *enc_caps;
+ struct dpcd_caps *rx_caps = &link->dpcd_caps;
+ enum dc_dp_training_pattern pattern = DP_TRAINING_PATTERN_SEQUENCE_2;
+
+ link_enc = link_enc_cfg_get_link_enc(link);
+ ASSERT(link_enc);
+ enc_caps = &link_enc->features;
+
+ switch (link_dp_get_encoding_format(link_settings)) {
+ case DP_8b_10b_ENCODING:
+ if (enc_caps->flags.bits.IS_TPS4_CAPABLE &&
+ rx_caps->max_down_spread.bits.TPS4_SUPPORTED)
+ pattern = DP_TRAINING_PATTERN_SEQUENCE_4;
+ else if (enc_caps->flags.bits.IS_TPS3_CAPABLE &&
+ rx_caps->max_ln_count.bits.TPS3_SUPPORTED)
+ pattern = DP_TRAINING_PATTERN_SEQUENCE_3;
+ else
+ pattern = DP_TRAINING_PATTERN_SEQUENCE_2;
+ break;
+ case DP_128b_132b_ENCODING:
+ pattern = DP_128b_132b_TPS2;
+ break;
+ default:
+ pattern = DP_TRAINING_PATTERN_SEQUENCE_2;
+ break;
+ }
+ return pattern;
+}
+
+enum lttpr_mode dp_decide_lttpr_mode(struct dc_link *link,
+ struct dc_link_settings *link_setting)
+{
+ enum dp_link_encoding encoding = link_dp_get_encoding_format(link_setting);
+
+ if (encoding == DP_8b_10b_ENCODING)
+ return dp_decide_8b_10b_lttpr_mode(link);
+ else if (encoding == DP_128b_132b_ENCODING)
+ return dp_decide_128b_132b_lttpr_mode(link);
+
+ ASSERT(0);
+ return LTTPR_MODE_NON_LTTPR;
+}
+
+void dp_decide_lane_settings(
+ const struct link_training_settings *lt_settings,
+ const union lane_adjust ln_adjust[LANE_COUNT_DP_MAX],
+ struct dc_lane_settings hw_lane_settings[LANE_COUNT_DP_MAX],
+ union dpcd_training_lane *dpcd_lane_settings)
+{
+ uint32_t lane;
+
+ for (lane = 0; lane < LANE_COUNT_DP_MAX; lane++) {
+ if (link_dp_get_encoding_format(&lt_settings->link_settings) ==
+ DP_8b_10b_ENCODING) {
+ hw_lane_settings[lane].VOLTAGE_SWING =
+ (enum dc_voltage_swing)(ln_adjust[lane].bits.
+ VOLTAGE_SWING_LANE);
+ hw_lane_settings[lane].PRE_EMPHASIS =
+ (enum dc_pre_emphasis)(ln_adjust[lane].bits.
+ PRE_EMPHASIS_LANE);
+ } else if (link_dp_get_encoding_format(&lt_settings->link_settings) ==
+ DP_128b_132b_ENCODING) {
+ hw_lane_settings[lane].FFE_PRESET.raw =
+ ln_adjust[lane].tx_ffe.PRESET_VALUE;
+ }
+ }
+ dp_hw_to_dpcd_lane_settings(lt_settings, hw_lane_settings, dpcd_lane_settings);
+
+ if (lt_settings->disallow_per_lane_settings) {
+ /* we find the maximum of the requested settings across all lanes*/
+ /* and set this maximum for all lanes*/
+ maximize_lane_settings(lt_settings, hw_lane_settings);
+ override_lane_settings(lt_settings, hw_lane_settings);
+
+ if (lt_settings->always_match_dpcd_with_hw_lane_settings)
+ dp_hw_to_dpcd_lane_settings(lt_settings, hw_lane_settings, dpcd_lane_settings);
+ }
+
+}
+
+void dp_decide_training_settings(
+ struct dc_link *link,
+ const struct dc_link_settings *link_settings,
+ struct link_training_settings *lt_settings)
+{
+ if (link_dp_get_encoding_format(link_settings) == DP_8b_10b_ENCODING)
+ decide_8b_10b_training_settings(link, link_settings, lt_settings);
+ else if (link_dp_get_encoding_format(link_settings) == DP_128b_132b_ENCODING)
+ decide_128b_132b_training_settings(link, link_settings, lt_settings);
+}
+
+
+enum dc_status configure_lttpr_mode_transparent(struct dc_link *link)
+{
+ uint8_t repeater_mode = DP_PHY_REPEATER_MODE_TRANSPARENT;
+
+ DC_LOG_HW_LINK_TRAINING("%s\n Set LTTPR to Transparent Mode\n", __func__);
+ return core_link_write_dpcd(link,
+ DP_PHY_REPEATER_MODE,
+ (uint8_t *)&repeater_mode,
+ sizeof(repeater_mode));
+}
+
+static enum dc_status configure_lttpr_mode_non_transparent(
+ struct dc_link *link,
+ const struct link_training_settings *lt_settings)
+{
+ /* aux timeout is already set to extended */
+ /* RESET/SET lttpr mode to enable non transparent mode */
+ uint8_t repeater_cnt;
+ uint32_t aux_interval_address;
+ uint8_t repeater_id;
+ enum dc_status result = DC_ERROR_UNEXPECTED;
+ uint8_t repeater_mode = DP_PHY_REPEATER_MODE_TRANSPARENT;
+ const struct dc *dc = link->dc;
+
+ enum dp_link_encoding encoding = dc->link_srv->dp_get_encoding_format(&lt_settings->link_settings);
+
+ if (encoding == DP_8b_10b_ENCODING) {
+ DC_LOG_HW_LINK_TRAINING("%s\n Set LTTPR to Transparent Mode\n", __func__);
+ result = core_link_write_dpcd(link,
+ DP_PHY_REPEATER_MODE,
+ (uint8_t *)&repeater_mode,
+ sizeof(repeater_mode));
+
+ }
+
+ if (result == DC_OK) {
+ link->dpcd_caps.lttpr_caps.mode = repeater_mode;
+ }
+
+ if (lt_settings->lttpr_mode == LTTPR_MODE_NON_TRANSPARENT) {
+
+ DC_LOG_HW_LINK_TRAINING("%s\n Set LTTPR to Non Transparent Mode\n", __func__);
+
+ repeater_mode = DP_PHY_REPEATER_MODE_NON_TRANSPARENT;
+ result = core_link_write_dpcd(link,
+ DP_PHY_REPEATER_MODE,
+ (uint8_t *)&repeater_mode,
+ sizeof(repeater_mode));
+
+ if (result == DC_OK) {
+ link->dpcd_caps.lttpr_caps.mode = repeater_mode;
+ }
+
+ if (encoding == DP_8b_10b_ENCODING) {
+ repeater_cnt = dp_parse_lttpr_repeater_count(link->dpcd_caps.lttpr_caps.phy_repeater_cnt);
+
+ /* Driver does not need to train the first hop. Skip DPCD read and clear
+ * AUX_RD_INTERVAL for DPTX-to-DPIA hop.
+ */
+ if (link->ep_type == DISPLAY_ENDPOINT_USB4_DPIA)
+ link->dpcd_caps.lttpr_caps.aux_rd_interval[--repeater_cnt] = 0;
+
+ for (repeater_id = repeater_cnt; repeater_id > 0; repeater_id--) {
+ aux_interval_address = DP_TRAINING_AUX_RD_INTERVAL_PHY_REPEATER1 +
+ ((DP_REPEATER_CONFIGURATION_AND_STATUS_SIZE) * (repeater_id - 1));
+ core_link_read_dpcd(
+ link,
+ aux_interval_address,
+ (uint8_t *)&link->dpcd_caps.lttpr_caps.aux_rd_interval[repeater_id - 1],
+ sizeof(link->dpcd_caps.lttpr_caps.aux_rd_interval[repeater_id - 1]));
+ link->dpcd_caps.lttpr_caps.aux_rd_interval[repeater_id - 1] &= 0x7F;
+ }
+ }
+ }
+
+ return result;
+}
+
+enum dc_status dpcd_configure_lttpr_mode(struct dc_link *link, struct link_training_settings *lt_settings)
+{
+ enum dc_status status = DC_OK;
+
+ if (lt_settings->lttpr_mode == LTTPR_MODE_TRANSPARENT)
+ status = configure_lttpr_mode_transparent(link);
+
+ else if (lt_settings->lttpr_mode == LTTPR_MODE_NON_TRANSPARENT)
+ status = configure_lttpr_mode_non_transparent(link, lt_settings);
+
+ return status;
+}
+
+void repeater_training_done(struct dc_link *link, uint32_t offset)
+{
+ union dpcd_training_pattern dpcd_pattern = {0};
+
+ const uint32_t dpcd_base_lt_offset =
+ DP_TRAINING_PATTERN_SET_PHY_REPEATER1 +
+ ((DP_REPEATER_CONFIGURATION_AND_STATUS_SIZE) * (offset - 1));
+ /* Set training not in progress*/
+ dpcd_pattern.v1_4.TRAINING_PATTERN_SET = DPCD_TRAINING_PATTERN_VIDEOIDLE;
+
+ core_link_write_dpcd(
+ link,
+ dpcd_base_lt_offset,
+ &dpcd_pattern.raw,
+ 1);
+
+ DC_LOG_HW_LINK_TRAINING("%s\n LTTPR Id: %d 0x%X pattern = %x\n",
+ __func__,
+ offset,
+ dpcd_base_lt_offset,
+ dpcd_pattern.v1_4.TRAINING_PATTERN_SET);
+}
+
+static void dpcd_exit_training_mode(struct dc_link *link, enum dp_link_encoding encoding)
+{
+ uint8_t sink_status = 0;
+ uint8_t i;
+
+ /* clear training pattern set */
+ dpcd_set_training_pattern(link, DP_TRAINING_PATTERN_VIDEOIDLE);
+
+ if (encoding == DP_128b_132b_ENCODING) {
+ /* poll for intra-hop disable */
+ for (i = 0; i < 10; i++) {
+ if ((core_link_read_dpcd(link, DP_SINK_STATUS, &sink_status, 1) == DC_OK) &&
+ (sink_status & DP_INTRA_HOP_AUX_REPLY_INDICATION) == 0)
+ break;
+ fsleep(1000);
+ }
+ }
+}
+
+enum dc_status dpcd_configure_channel_coding(struct dc_link *link,
+ struct link_training_settings *lt_settings)
+{
+ enum dp_link_encoding encoding =
+ link_dp_get_encoding_format(
+ &lt_settings->link_settings);
+ enum dc_status status;
+
+ status = core_link_write_dpcd(
+ link,
+ DP_MAIN_LINK_CHANNEL_CODING_SET,
+ (uint8_t *) &encoding,
+ 1);
+ DC_LOG_HW_LINK_TRAINING("%s:\n 0x%X MAIN_LINK_CHANNEL_CODING_SET = %x\n",
+ __func__,
+ DP_MAIN_LINK_CHANNEL_CODING_SET,
+ encoding);
+
+ return status;
+}
+
+void dpcd_set_training_pattern(
+ struct dc_link *link,
+ enum dc_dp_training_pattern training_pattern)
+{
+ union dpcd_training_pattern dpcd_pattern = {0};
+
+ dpcd_pattern.v1_4.TRAINING_PATTERN_SET =
+ dp_training_pattern_to_dpcd_training_pattern(
+ link, training_pattern);
+
+ core_link_write_dpcd(
+ link,
+ DP_TRAINING_PATTERN_SET,
+ &dpcd_pattern.raw,
+ 1);
+
+ DC_LOG_HW_LINK_TRAINING("%s\n %x pattern = %x\n",
+ __func__,
+ DP_TRAINING_PATTERN_SET,
+ dpcd_pattern.v1_4.TRAINING_PATTERN_SET);
+}
+
+enum dc_status dpcd_set_link_settings(
+ struct dc_link *link,
+ const struct link_training_settings *lt_settings)
+{
+ uint8_t rate;
+ enum dc_status status;
+
+ union down_spread_ctrl downspread = {0};
+ union lane_count_set lane_count_set = {0};
+
+ 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 (link->ep_type == DISPLAY_ENDPOINT_PHY &&
+ 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;
+ }
+
+ status = core_link_write_dpcd(link, DP_DOWNSPREAD_CTRL,
+ &downspread.raw, sizeof(downspread));
+
+ status = core_link_write_dpcd(link, DP_LANE_COUNT_SET,
+ &lane_count_set.raw, 1);
+
+ if (link->dpcd_caps.dpcd_rev.raw >= DPCD_REV_13 &&
+ lt_settings->link_settings.use_link_rate_set == true) {
+ rate = 0;
+ /* WA for some MUX chips that will power down with eDP and lose supported
+ * link rate set for eDP 1.4. Source reads DPCD 0x010 again to ensure
+ * MUX chip gets link rate set back before link training.
+ */
+ if (link->connector_signal == SIGNAL_TYPE_EDP) {
+ uint8_t supported_link_rates[16];
+
+ core_link_read_dpcd(link, DP_SUPPORTED_LINK_RATES,
+ supported_link_rates, sizeof(supported_link_rates));
+ }
+ status = core_link_write_dpcd(link, DP_LINK_BW_SET, &rate, 1);
+ status = core_link_write_dpcd(link, DP_LINK_RATE_SET,
+ &lt_settings->link_settings.link_rate_set, 1);
+ } else {
+ rate = get_dpcd_link_rate(&lt_settings->link_settings);
+
+ status = core_link_write_dpcd(link, DP_LINK_BW_SET, &rate, 1);
+ }
+
+ if (rate) {
+ 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);
+ } else {
+ DC_LOG_HW_LINK_TRAINING("%s\n %x rate set = %x\n %x lane = %x framing = %x\n %x spread = %x\n",
+ __func__,
+ DP_LINK_RATE_SET,
+ lt_settings->link_settings.link_rate_set,
+ DP_LANE_COUNT_SET,
+ lt_settings->link_settings.lane_count,
+ lt_settings->enhanced_framing,
+ DP_DOWNSPREAD_CTRL,
+ lt_settings->link_settings.link_spread);
+ }
+
+ return status;
+}
+
+enum dc_status dpcd_set_lane_settings(
+ struct dc_link *link,
+ const struct link_training_settings *link_training_setting,
+ uint32_t offset)
+{
+ unsigned int lane0_set_address;
+ enum dc_status status;
+ lane0_set_address = DP_TRAINING_LANE0_SET;
+
+ if (is_repeater(link_training_setting, offset))
+ lane0_set_address = DP_TRAINING_LANE0_SET_PHY_REPEATER1 +
+ ((DP_REPEATER_CONFIGURATION_AND_STATUS_SIZE) * (offset - 1));
+
+ status = core_link_write_dpcd(link,
+ lane0_set_address,
+ (uint8_t *)(link_training_setting->dpcd_lane_settings),
+ link_training_setting->link_settings.lane_count);
+
+ if (is_repeater(link_training_setting, offset)) {
+ DC_LOG_HW_LINK_TRAINING("%s\n LTTPR Repeater ID: %d\n"
+ " 0x%X VS set = %x PE set = %x max VS Reached = %x max PE Reached = %x\n",
+ __func__,
+ offset,
+ lane0_set_address,
+ link_training_setting->dpcd_lane_settings[0].bits.VOLTAGE_SWING_SET,
+ link_training_setting->dpcd_lane_settings[0].bits.PRE_EMPHASIS_SET,
+ link_training_setting->dpcd_lane_settings[0].bits.MAX_SWING_REACHED,
+ link_training_setting->dpcd_lane_settings[0].bits.MAX_PRE_EMPHASIS_REACHED);
+
+ } else {
+ DC_LOG_HW_LINK_TRAINING("%s\n 0x%X VS set = %x PE set = %x max VS Reached = %x max PE Reached = %x\n",
+ __func__,
+ lane0_set_address,
+ link_training_setting->dpcd_lane_settings[0].bits.VOLTAGE_SWING_SET,
+ link_training_setting->dpcd_lane_settings[0].bits.PRE_EMPHASIS_SET,
+ link_training_setting->dpcd_lane_settings[0].bits.MAX_SWING_REACHED,
+ link_training_setting->dpcd_lane_settings[0].bits.MAX_PRE_EMPHASIS_REACHED);
+ }
+
+ return status;
+}
+
+void dpcd_set_lt_pattern_and_lane_settings(
+ struct dc_link *link,
+ const struct link_training_settings *lt_settings,
+ enum dc_dp_training_pattern pattern,
+ uint32_t offset)
+{
+ uint32_t dpcd_base_lt_offset;
+ uint8_t dpcd_lt_buffer[5] = {0};
+ union dpcd_training_pattern dpcd_pattern = {0};
+ uint32_t size_in_bytes;
+ bool edp_workaround = false; /* TODO link_prop.INTERNAL */
+ dpcd_base_lt_offset = DP_TRAINING_PATTERN_SET;
+
+ if (is_repeater(lt_settings, offset))
+ dpcd_base_lt_offset = DP_TRAINING_PATTERN_SET_PHY_REPEATER1 +
+ ((DP_REPEATER_CONFIGURATION_AND_STATUS_SIZE) * (offset - 1));
+
+ /*****************************************************************
+ * DpcdAddress_TrainingPatternSet
+ *****************************************************************/
+ dpcd_pattern.v1_4.TRAINING_PATTERN_SET =
+ dp_training_pattern_to_dpcd_training_pattern(link, pattern);
+
+ dpcd_pattern.v1_4.SCRAMBLING_DISABLE =
+ dp_initialize_scrambling_data_symbols(link, pattern);
+
+ dpcd_lt_buffer[DP_TRAINING_PATTERN_SET - DP_TRAINING_PATTERN_SET]
+ = dpcd_pattern.raw;
+
+ if (is_repeater(lt_settings, offset)) {
+ DC_LOG_HW_LINK_TRAINING("%s\n LTTPR Repeater ID: %d\n 0x%X pattern = %x\n",
+ __func__,
+ offset,
+ dpcd_base_lt_offset,
+ dpcd_pattern.v1_4.TRAINING_PATTERN_SET);
+ } else {
+ DC_LOG_HW_LINK_TRAINING("%s\n 0x%X pattern = %x\n",
+ __func__,
+ dpcd_base_lt_offset,
+ dpcd_pattern.v1_4.TRAINING_PATTERN_SET);
+ }
+
+ /* concatenate everything into one buffer*/
+ size_in_bytes = lt_settings->link_settings.lane_count *
+ sizeof(lt_settings->dpcd_lane_settings[0]);
+
+ // 0x00103 - 0x00102
+ memmove(
+ &dpcd_lt_buffer[DP_TRAINING_LANE0_SET - DP_TRAINING_PATTERN_SET],
+ lt_settings->dpcd_lane_settings,
+ size_in_bytes);
+
+ if (is_repeater(lt_settings, offset)) {
+ if (link_dp_get_encoding_format(&lt_settings->link_settings) ==
+ DP_128b_132b_ENCODING)
+ DC_LOG_HW_LINK_TRAINING("%s:\n LTTPR Repeater ID: %d\n"
+ " 0x%X TX_FFE_PRESET_VALUE = %x\n",
+ __func__,
+ offset,
+ dpcd_base_lt_offset,
+ lt_settings->dpcd_lane_settings[0].tx_ffe.PRESET_VALUE);
+ else if (link_dp_get_encoding_format(&lt_settings->link_settings) ==
+ DP_8b_10b_ENCODING)
+ DC_LOG_HW_LINK_TRAINING("%s:\n LTTPR Repeater ID: %d\n"
+ " 0x%X VS set = %x PE set = %x max VS Reached = %x max PE Reached = %x\n",
+ __func__,
+ offset,
+ dpcd_base_lt_offset,
+ lt_settings->dpcd_lane_settings[0].bits.VOLTAGE_SWING_SET,
+ lt_settings->dpcd_lane_settings[0].bits.PRE_EMPHASIS_SET,
+ lt_settings->dpcd_lane_settings[0].bits.MAX_SWING_REACHED,
+ lt_settings->dpcd_lane_settings[0].bits.MAX_PRE_EMPHASIS_REACHED);
+ } else {
+ if (link_dp_get_encoding_format(&lt_settings->link_settings) ==
+ DP_128b_132b_ENCODING)
+ DC_LOG_HW_LINK_TRAINING("%s:\n 0x%X TX_FFE_PRESET_VALUE = %x\n",
+ __func__,
+ dpcd_base_lt_offset,
+ lt_settings->dpcd_lane_settings[0].tx_ffe.PRESET_VALUE);
+ else if (link_dp_get_encoding_format(&lt_settings->link_settings) ==
+ DP_8b_10b_ENCODING)
+ DC_LOG_HW_LINK_TRAINING("%s:\n 0x%X VS set = %x PE set = %x max VS Reached = %x max PE Reached = %x\n",
+ __func__,
+ dpcd_base_lt_offset,
+ lt_settings->dpcd_lane_settings[0].bits.VOLTAGE_SWING_SET,
+ lt_settings->dpcd_lane_settings[0].bits.PRE_EMPHASIS_SET,
+ lt_settings->dpcd_lane_settings[0].bits.MAX_SWING_REACHED,
+ lt_settings->dpcd_lane_settings[0].bits.MAX_PRE_EMPHASIS_REACHED);
+ }
+ if (edp_workaround) {
+ /* for eDP write in 2 parts because the 5-byte burst is
+ * causing issues on some eDP panels (EPR#366724)
+ */
+ core_link_write_dpcd(
+ link,
+ DP_TRAINING_PATTERN_SET,
+ &dpcd_pattern.raw,
+ sizeof(dpcd_pattern.raw));
+
+ core_link_write_dpcd(
+ link,
+ DP_TRAINING_LANE0_SET,
+ (uint8_t *)(lt_settings->dpcd_lane_settings),
+ size_in_bytes);
+
+ } else if (link_dp_get_encoding_format(&lt_settings->link_settings) ==
+ DP_128b_132b_ENCODING) {
+ core_link_write_dpcd(
+ link,
+ dpcd_base_lt_offset,
+ dpcd_lt_buffer,
+ sizeof(dpcd_lt_buffer));
+ } else
+ /* write it all in (1 + number-of-lanes)-byte burst*/
+ core_link_write_dpcd(
+ link,
+ dpcd_base_lt_offset,
+ dpcd_lt_buffer,
+ size_in_bytes + sizeof(dpcd_pattern.raw));
+}
+
+void start_clock_recovery_pattern_early(struct dc_link *link,
+ const struct link_resource *link_res,
+ struct link_training_settings *lt_settings,
+ uint32_t offset)
+{
+ DC_LOG_HW_LINK_TRAINING("%s\n GPU sends TPS1. Wait 400us.\n",
+ __func__);
+ dp_set_hw_training_pattern(link, link_res, lt_settings->pattern_for_cr, offset);
+ dp_set_hw_lane_settings(link, link_res, lt_settings, offset);
+ udelay(400);
+}
+
+void dp_set_hw_test_pattern(
+ struct dc_link *link,
+ const struct link_resource *link_res,
+ enum dp_test_pattern test_pattern,
+ uint8_t *custom_pattern,
+ uint32_t custom_pattern_size)
+{
+ const struct link_hwss *link_hwss = get_link_hwss(link, link_res);
+ struct encoder_set_dp_phy_pattern_param pattern_param = {0};
+
+ pattern_param.dp_phy_pattern = test_pattern;
+ pattern_param.custom_pattern = custom_pattern;
+ pattern_param.custom_pattern_size = custom_pattern_size;
+ pattern_param.dp_panel_mode = dp_get_panel_mode(link);
+
+ if (link_hwss->ext.set_dp_link_test_pattern)
+ link_hwss->ext.set_dp_link_test_pattern(link, link_res, &pattern_param);
+}
+
+bool dp_set_hw_training_pattern(
+ struct dc_link *link,
+ const struct link_resource *link_res,
+ enum dc_dp_training_pattern pattern,
+ uint32_t offset)
+{
+ enum dp_test_pattern test_pattern = DP_TEST_PATTERN_UNSUPPORTED;
+
+ switch (pattern) {
+ case DP_TRAINING_PATTERN_SEQUENCE_1:
+ test_pattern = DP_TEST_PATTERN_TRAINING_PATTERN1;
+ break;
+ case DP_TRAINING_PATTERN_SEQUENCE_2:
+ test_pattern = DP_TEST_PATTERN_TRAINING_PATTERN2;
+ break;
+ case DP_TRAINING_PATTERN_SEQUENCE_3:
+ test_pattern = DP_TEST_PATTERN_TRAINING_PATTERN3;
+ break;
+ case DP_TRAINING_PATTERN_SEQUENCE_4:
+ test_pattern = DP_TEST_PATTERN_TRAINING_PATTERN4;
+ break;
+ case DP_128b_132b_TPS1:
+ test_pattern = DP_TEST_PATTERN_128b_132b_TPS1_TRAINING_MODE;
+ break;
+ case DP_128b_132b_TPS2:
+ test_pattern = DP_TEST_PATTERN_128b_132b_TPS2_TRAINING_MODE;
+ break;
+ default:
+ break;
+ }
+
+ dp_set_hw_test_pattern(link, link_res, test_pattern, NULL, 0);
+
+ return true;
+}
+
+static bool perform_post_lt_adj_req_sequence(
+ struct dc_link *link,
+ const struct link_resource *link_res,
+ struct link_training_settings *lt_settings)
+{
+ enum dc_lane_count lane_count =
+ lt_settings->link_settings.lane_count;
+
+ uint32_t adj_req_count;
+ uint32_t adj_req_timer;
+ bool req_drv_setting_changed;
+ uint32_t lane;
+ union lane_status dpcd_lane_status[LANE_COUNT_DP_MAX] = {0};
+ union lane_align_status_updated dpcd_lane_status_updated = {0};
+ union lane_adjust dpcd_lane_adjust[LANE_COUNT_DP_MAX] = {0};
+
+ req_drv_setting_changed = false;
+ for (adj_req_count = 0; adj_req_count < POST_LT_ADJ_REQ_LIMIT;
+ adj_req_count++) {
+
+ req_drv_setting_changed = false;
+
+ for (adj_req_timer = 0;
+ adj_req_timer < POST_LT_ADJ_REQ_TIMEOUT;
+ adj_req_timer++) {
+
+ dp_get_lane_status_and_lane_adjust(
+ link,
+ lt_settings,
+ dpcd_lane_status,
+ &dpcd_lane_status_updated,
+ dpcd_lane_adjust,
+ DPRX);
+
+ if (dpcd_lane_status_updated.bits.
+ POST_LT_ADJ_REQ_IN_PROGRESS == 0)
+ return true;
+
+ if (!dp_is_cr_done(lane_count, dpcd_lane_status))
+ return false;
+
+ 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))
+ return false;
+
+ for (lane = 0; lane < (uint32_t)(lane_count); lane++) {
+
+ if (lt_settings->
+ dpcd_lane_settings[lane].bits.VOLTAGE_SWING_SET !=
+ dpcd_lane_adjust[lane].bits.VOLTAGE_SWING_LANE ||
+ lt_settings->dpcd_lane_settings[lane].bits.PRE_EMPHASIS_SET !=
+ dpcd_lane_adjust[lane].bits.PRE_EMPHASIS_LANE) {
+
+ req_drv_setting_changed = true;
+ break;
+ }
+ }
+
+ if (req_drv_setting_changed) {
+ dp_decide_lane_settings(lt_settings, dpcd_lane_adjust,
+ lt_settings->hw_lane_settings, lt_settings->dpcd_lane_settings);
+
+ dp_set_drive_settings(link,
+ link_res,
+ lt_settings);
+ break;
+ }
+
+ msleep(1);
+ }
+
+ if (!req_drv_setting_changed) {
+ DC_LOG_WARNING("%s: Post Link Training Adjust Request Timed out\n",
+ __func__);
+
+ ASSERT(0);
+ return true;
+ }
+ }
+ DC_LOG_WARNING("%s: Post Link Training Adjust Request limit reached\n",
+ __func__);
+
+ ASSERT(0);
+ return true;
+
+}
+
+static enum link_training_result dp_transition_to_video_idle(
+ struct dc_link *link,
+ const struct link_resource *link_res,
+ struct link_training_settings *lt_settings,
+ enum link_training_result status)
+{
+ union lane_count_set lane_count_set = {0};
+
+ /* 4. mainlink output idle pattern*/
+ dp_set_hw_test_pattern(link, link_res, DP_TEST_PATTERN_VIDEO_MODE, NULL, 0);
+
+ /*
+ * 5. post training adjust if required
+ * If the upstream DPTX and downstream DPRX both support TPS4,
+ * TPS4 must be used instead of POST_LT_ADJ_REQ.
+ */
+ if (link->dpcd_caps.max_ln_count.bits.POST_LT_ADJ_REQ_SUPPORTED != 1 ||
+ lt_settings->pattern_for_eq >= DP_TRAINING_PATTERN_SEQUENCE_4) {
+ /* 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 = dp_check_link_loss_status(link, lt_settings);
+ }
+ return status;
+ }
+
+ if (status == LINK_TRAINING_SUCCESS &&
+ perform_post_lt_adj_req_sequence(link, link_res, lt_settings) == 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 = lt_settings->enhanced_framing;
+ lane_count_set.bits.POST_LT_ADJ_REQ_GRANTED = 0;
+
+ core_link_write_dpcd(
+ link,
+ DP_LANE_COUNT_SET,
+ &lane_count_set.raw,
+ sizeof(lane_count_set));
+
+ return status;
+}
+
+enum link_training_result dp_perform_link_training(
+ struct dc_link *link,
+ const struct link_resource *link_res,
+ const struct dc_link_settings *link_settings,
+ bool skip_video_pattern)
+{
+ enum link_training_result status = LINK_TRAINING_SUCCESS;
+ struct link_training_settings lt_settings = {0};
+ enum dp_link_encoding encoding =
+ link_dp_get_encoding_format(link_settings);
+
+ /* decide training settings */
+ dp_decide_training_settings(
+ link,
+ link_settings,
+ &lt_settings);
+
+ override_training_settings(
+ link,
+ &link->preferred_training_settings,
+ &lt_settings);
+
+ /* reset previous training states */
+ dpcd_exit_training_mode(link, encoding);
+
+ /* configure link prior to entering training mode */
+ dpcd_configure_lttpr_mode(link, &lt_settings);
+ dp_set_fec_ready(link, link_res, lt_settings.should_set_fec_ready);
+ dpcd_configure_channel_coding(link, &lt_settings);
+
+ /* enter training mode:
+ * Per DP specs starting from here, DPTX device shall not issue
+ * Non-LT AUX transactions inside training mode.
+ */
+ if ((link->chip_caps & EXT_DISPLAY_PATH_CAPS__DP_FIXED_VS_EN) && encoding == DP_8b_10b_ENCODING)
+ if (link->dc->config.use_old_fixed_vs_sequence)
+ status = dp_perform_fixed_vs_pe_training_sequence_legacy(link, link_res, &lt_settings);
+ else
+ status = dp_perform_fixed_vs_pe_training_sequence(link, link_res, &lt_settings);
+ else if (encoding == DP_8b_10b_ENCODING)
+ status = dp_perform_8b_10b_link_training(link, link_res, &lt_settings);
+ else if (encoding == DP_128b_132b_ENCODING)
+ status = dp_perform_128b_132b_link_training(link, link_res, &lt_settings);
+ else
+ ASSERT(0);
+
+ /* exit training mode */
+ dpcd_exit_training_mode(link, encoding);
+
+ /* switch to video idle */
+ if ((status == LINK_TRAINING_SUCCESS) || !skip_video_pattern)
+ status = dp_transition_to_video_idle(link,
+ link_res,
+ &lt_settings,
+ status);
+
+ /* dump debug data */
+ dp_log_training_result(link, &lt_settings, status);
+ if (status != LINK_TRAINING_SUCCESS)
+ link->ctx->dc->debug_data.ltFailCount++;
+ return status;
+}
+
+bool perform_link_training_with_retries(
+ const struct dc_link_settings *link_setting,
+ bool skip_video_pattern,
+ int attempts,
+ struct pipe_ctx *pipe_ctx,
+ enum signal_type signal,
+ bool do_fallback)
+{
+ int j;
+ uint8_t delay_between_attempts = LINK_TRAINING_RETRY_DELAY;
+ struct dc_stream_state *stream = pipe_ctx->stream;
+ struct dc_link *link = stream->link;
+ enum dp_panel_mode panel_mode = dp_get_panel_mode(link);
+ enum link_training_result status = LINK_TRAINING_CR_FAIL_LANE0;
+ struct dc_link_settings cur_link_settings = *link_setting;
+ struct dc_link_settings max_link_settings = *link_setting;
+ const struct link_hwss *link_hwss = get_link_hwss(link, &pipe_ctx->link_res);
+ int fail_count = 0;
+ bool is_link_bw_low = false; /* link bandwidth < stream bandwidth */
+ bool is_link_bw_min = /* RBR x 1 */
+ (cur_link_settings.link_rate <= LINK_RATE_LOW) &&
+ (cur_link_settings.lane_count <= LANE_COUNT_ONE);
+
+ dp_trace_commit_lt_init(link);
+
+
+ if (link_dp_get_encoding_format(&cur_link_settings) == DP_8b_10b_ENCODING)
+ /* We need to do this before the link training to ensure the idle
+ * pattern in SST mode will be sent right after the link training
+ */
+ link_hwss->setup_stream_encoder(pipe_ctx);
+
+ dp_trace_set_lt_start_timestamp(link, false);
+ j = 0;
+ while (j < attempts && fail_count < (attempts * 10)) {
+
+ DC_LOG_HW_LINK_TRAINING("%s: Beginning link(%d) training attempt %u of %d @ rate(%d) x lane(%d) @ spread = %x\n",
+ __func__, link->link_index, (unsigned int)j + 1, attempts,
+ cur_link_settings.link_rate, cur_link_settings.lane_count,
+ cur_link_settings.link_spread);
+
+ dp_enable_link_phy(
+ link,
+ &pipe_ctx->link_res,
+ signal,
+ pipe_ctx->clock_source->id,
+ &cur_link_settings);
+
+ if (stream->sink_patches.dppowerup_delay > 0) {
+ int delay_dp_power_up_in_ms = stream->sink_patches.dppowerup_delay;
+
+ msleep(delay_dp_power_up_in_ms);
+ }
+
+ if (panel_mode == DP_PANEL_MODE_EDP) {
+ struct cp_psp *cp_psp = &stream->ctx->cp_psp;
+
+ if (cp_psp && cp_psp->funcs.enable_assr) {
+ /* ASSR is bound to fail with unsigned PSP
+ * verstage used during devlopment phase.
+ * Report and continue with eDP panel mode to
+ * perform eDP link training with right settings
+ */
+ bool result;
+ result = cp_psp->funcs.enable_assr(cp_psp->handle, link);
+ if (!result && link->panel_mode != DP_PANEL_MODE_EDP)
+ panel_mode = DP_PANEL_MODE_DEFAULT;
+ }
+ }
+
+ dp_set_panel_mode(link, panel_mode);
+
+ if (link->aux_access_disabled) {
+ dp_perform_link_training_skip_aux(link, &pipe_ctx->link_res, &cur_link_settings);
+ return true;
+ } else {
+ /** @todo Consolidate USB4 DP and DPx.x training. */
+ if (link->ep_type == DISPLAY_ENDPOINT_USB4_DPIA) {
+ status = dpia_perform_link_training(
+ link,
+ &pipe_ctx->link_res,
+ &cur_link_settings,
+ skip_video_pattern);
+
+ /* Transmit idle pattern once training successful. */
+ if (status == LINK_TRAINING_SUCCESS && !is_link_bw_low) {
+ dp_set_hw_test_pattern(link, &pipe_ctx->link_res, DP_TEST_PATTERN_VIDEO_MODE, NULL, 0);
+ // Update verified link settings to current one
+ // Because DPIA LT might fallback to lower link setting.
+ if (stream->signal == SIGNAL_TYPE_DISPLAY_PORT_MST) {
+ link->verified_link_cap.link_rate = link->cur_link_settings.link_rate;
+ link->verified_link_cap.lane_count = link->cur_link_settings.lane_count;
+ dm_helpers_dp_mst_update_branch_bandwidth(link->ctx, link);
+ }
+ }
+ } else {
+ status = dp_perform_link_training(
+ link,
+ &pipe_ctx->link_res,
+ &cur_link_settings,
+ skip_video_pattern);
+ }
+
+ dp_trace_lt_total_count_increment(link, false);
+ dp_trace_lt_result_update(link, status, false);
+ dp_trace_set_lt_end_timestamp(link, false);
+ if (status == LINK_TRAINING_SUCCESS && !is_link_bw_low)
+ return true;
+ }
+
+ fail_count++;
+ dp_trace_lt_fail_count_update(link, fail_count, false);
+ if (link->ep_type == DISPLAY_ENDPOINT_PHY) {
+ /* latest link training still fail or link training is aborted
+ * skip delay and keep PHY on
+ */
+ if (j == (attempts - 1) || (status == LINK_TRAINING_ABORT))
+ break;
+ }
+
+ if (j == (attempts - 1)) {
+ DC_LOG_WARNING(
+ "%s: Link(%d) training attempt %u of %d failed @ rate(%d) x lane(%d) @ spread = %x : fail reason:(%d)\n",
+ __func__, link->link_index, (unsigned int)j + 1, attempts,
+ cur_link_settings.link_rate, cur_link_settings.lane_count,
+ cur_link_settings.link_spread, status);
+ } else {
+ DC_LOG_HW_LINK_TRAINING(
+ "%s: Link(%d) training attempt %u of %d failed @ rate(%d) x lane(%d) @ spread = %x : fail reason:(%d)\n",
+ __func__, link->link_index, (unsigned int)j + 1, attempts,
+ cur_link_settings.link_rate, cur_link_settings.lane_count,
+ cur_link_settings.link_spread, status);
+ }
+
+ dp_disable_link_phy(link, &pipe_ctx->link_res, signal);
+
+ /* Abort link training if failure due to sink being unplugged. */
+ if (status == LINK_TRAINING_ABORT) {
+ enum dc_connection_type type = dc_connection_none;
+
+ link_detect_connection_type(link, &type);
+ if (type == dc_connection_none) {
+ DC_LOG_HW_LINK_TRAINING("%s: Aborting training because sink unplugged\n", __func__);
+ break;
+ }
+ }
+
+ /* Try to train again at original settings if:
+ * - not falling back between training attempts;
+ * - aborted previous attempt due to reasons other than sink unplug;
+ * - successfully trained but at a link rate lower than that required by stream;
+ * - reached minimum link bandwidth.
+ */
+ if (!do_fallback || (status == LINK_TRAINING_ABORT) ||
+ (status == LINK_TRAINING_SUCCESS && is_link_bw_low) ||
+ is_link_bw_min) {
+ j++;
+ cur_link_settings = *link_setting;
+ delay_between_attempts += LINK_TRAINING_RETRY_DELAY;
+ is_link_bw_low = false;
+ is_link_bw_min = (cur_link_settings.link_rate <= LINK_RATE_LOW) &&
+ (cur_link_settings.lane_count <= LANE_COUNT_ONE);
+
+ } else if (do_fallback) { /* Try training at lower link bandwidth if doing fallback. */
+ uint32_t req_bw;
+ uint32_t link_bw;
+ enum dc_link_encoding_format link_encoding = DC_LINK_ENCODING_UNSPECIFIED;
+
+ decide_fallback_link_setting(link, &max_link_settings,
+ &cur_link_settings, status);
+
+ if (link_dp_get_encoding_format(&cur_link_settings) == DP_8b_10b_ENCODING)
+ link_encoding = DC_LINK_ENCODING_DP_8b_10b;
+ else if (link_dp_get_encoding_format(&cur_link_settings) == DP_128b_132b_ENCODING)
+ link_encoding = DC_LINK_ENCODING_DP_128b_132b;
+
+ /* Flag if reduced link bandwidth no longer meets stream requirements or fallen back to
+ * minimum link bandwidth.
+ */
+ req_bw = dc_bandwidth_in_kbps_from_timing(&stream->timing, link_encoding);
+ link_bw = dp_link_bandwidth_kbps(link, &cur_link_settings);
+ is_link_bw_low = (req_bw > link_bw);
+ is_link_bw_min = ((cur_link_settings.link_rate <= LINK_RATE_LOW) &&
+ (cur_link_settings.lane_count <= LANE_COUNT_ONE));
+
+ if (is_link_bw_low)
+ DC_LOG_WARNING(
+ "%s: Link(%d) bandwidth too low after fallback req_bw(%d) > link_bw(%d)\n",
+ __func__, link->link_index, req_bw, link_bw);
+ }
+
+ msleep(delay_between_attempts);
+ }
+
+ return false;
+}
+