From 8225367130666bf2961399a85913af1b4497d9b4 Mon Sep 17 00:00:00 2001 From: Jimmy Kizito Date: Wed, 7 Apr 2021 18:56:19 -0400 Subject: [PATCH] drm/amd/display: Add fallback and abort paths for DP link training. [Why] When enabling a DisplayPort stream: - Optionally reducing link bandwidth between failed link training attempts should progressively relax training requirements. - Abandoning link training altogether if a sink is unplugged should avoid unnecessary training attempts. [How] - Add fallback parameter to DP link training function and reduce link bandwidth between failed training attempts as long as stream bandwidth requirements are met. - Add training status for sink unplug and abort training when this status is reported. Signed-off-by: Jimmy Kizito Reviewed-by: Jun Lei Acked-by: Stylon Wang Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher --- drivers/gpu/drm/amd/display/dc/core/dc_link.c | 5 ++- drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 40 +++++++++++++++++----- drivers/gpu/drm/amd/display/dc/core/dc_link_hwss.c | 3 +- drivers/gpu/drm/amd/display/dc/inc/dc_link_dp.h | 3 +- .../drm/amd/display/include/link_service_types.h | 2 ++ 5 files changed, 42 insertions(+), 11 deletions(-) diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link.c b/drivers/gpu/drm/amd/display/dc/core/dc_link.c index d040d23..c4405eba 100644 --- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c +++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c @@ -1750,6 +1750,8 @@ static enum dc_status enable_link_dp(struct dc_state *state, bool apply_seamless_boot_optimization = false; uint32_t bl_oled_enable_delay = 50; // in ms const uint32_t post_oui_delay = 30; // 30ms + /* Reduce link bandwidth between failed link training attempts. */ + bool do_fallback = false; // check for seamless boot for (i = 0; i < state->stream_count; i++) { @@ -1788,7 +1790,8 @@ static enum dc_status enable_link_dp(struct dc_state *state, skip_video_pattern, LINK_TRAINING_ATTEMPTS, pipe_ctx, - pipe_ctx->stream->signal)) { + pipe_ctx->stream->signal, + do_fallback)) { link->cur_link_settings = link_settings; status = DC_OK; } else { 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 a87613f..dd95d00 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 @@ -1701,18 +1701,31 @@ bool perform_link_training_with_retries( bool skip_video_pattern, int attempts, struct pipe_ctx *pipe_ctx, - enum signal_type signal) + enum signal_type signal, + bool do_fallback) { uint8_t 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; + struct link_encoder *link_enc; + enum link_training_result status = LINK_TRAINING_CR_FAIL_LANE0; + struct dc_link_settings currnet_setting = *link_setting; + + /* Dynamically assigned link encoders associated with stream rather than + * link. + */ + if (link->dc->res_pool->funcs->link_encs_assign) + link_enc = stream->link_enc; + else + link_enc = link->link_enc; + ASSERT(link_enc); /* 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->link_enc->funcs->connect_dig_be_to_fe(link->link_enc, + link_enc->funcs->connect_dig_be_to_fe(link_enc, pipe_ctx->stream_res.stream_enc->id, true); for (j = 0; j < attempts; ++j) { @@ -1724,7 +1737,7 @@ bool perform_link_training_with_retries( link, signal, pipe_ctx->clock_source->id, - link_setting); + &currnet_setting); if (stream->sink_patches.dppowerup_delay > 0) { int delay_dp_power_up_in_ms = stream->sink_patches.dppowerup_delay; @@ -1739,14 +1752,12 @@ bool perform_link_training_with_retries( panel_mode != DP_PANEL_MODE_DEFAULT); if (link->aux_access_disabled) { - dc_link_dp_perform_link_training_skip_aux(link, link_setting); + dc_link_dp_perform_link_training_skip_aux(link, &currnet_setting); return true; } else { - enum link_training_result status = LINK_TRAINING_CR_FAIL_LANE0; - status = dc_link_dp_perform_link_training( link, - link_setting, + &currnet_setting, skip_video_pattern); if (status == LINK_TRAINING_SUCCESS) return true; @@ -1754,7 +1765,7 @@ bool perform_link_training_with_retries( /* latest link training still fail, skip delay and keep PHY on */ - if (j == (attempts - 1)) + if (j == (attempts - 1) && link->ep_type == DISPLAY_ENDPOINT_PHY) break; DC_LOG_WARNING("%s: Link training attempt %u of %d failed\n", @@ -1762,6 +1773,19 @@ bool perform_link_training_with_retries( dp_disable_link_phy(link, signal); + /* Abort link training if failure due to sink being unplugged. */ + if (status == LINK_TRAINING_ABORT) + break; + else if (do_fallback) { + decide_fallback_link_setting(*link_setting, &currnet_setting, status); + /* Fail link training if reduced link bandwidth no longer meets + * stream requirements. + */ + if (dc_bandwidth_in_kbps_from_timing(&stream->timing) < + dc_link_bandwidth_kbps(link, &currnet_setting)) + break; + } + msleep(delay_between_attempts); delay_between_attempts += LINK_TRAINING_RETRY_DELAY; diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_hwss.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_hwss.c index b426f87..13c5c4a 100644 --- a/drivers/gpu/drm/amd/display/dc/core/dc_link_hwss.c +++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_hwss.c @@ -384,7 +384,8 @@ void dp_retrain_link_dp_test(struct dc_link *link, skip_video_pattern, LINK_TRAINING_ATTEMPTS, &pipes[i], - SIGNAL_TYPE_DISPLAY_PORT); + SIGNAL_TYPE_DISPLAY_PORT, + false); link->dc->hwss.enable_stream(&pipes[i]); diff --git a/drivers/gpu/drm/amd/display/dc/inc/dc_link_dp.h b/drivers/gpu/drm/amd/display/dc/inc/dc_link_dp.h index 699de64..38e6fbf 100644 --- a/drivers/gpu/drm/amd/display/dc/inc/dc_link_dp.h +++ b/drivers/gpu/drm/amd/display/dc/inc/dc_link_dp.h @@ -65,7 +65,8 @@ bool perform_link_training_with_retries( bool skip_video_pattern, int attempts, struct pipe_ctx *pipe_ctx, - enum signal_type signal); + enum signal_type signal, + bool do_fallback); bool is_mst_supported(struct dc_link *link); 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 7392a89..5a250f4 100644 --- a/drivers/gpu/drm/amd/display/include/link_service_types.h +++ b/drivers/gpu/drm/amd/display/include/link_service_types.h @@ -68,6 +68,8 @@ enum link_training_result { LINK_TRAINING_LQA_FAIL, /* one of the CR,EQ or symbol lock is dropped */ LINK_TRAINING_LINK_LOSS, + /* Abort link training (because sink unplugged) */ + LINK_TRAINING_ABORT, }; struct link_training_settings { -- 2.7.4