From 824474ba38e27ccacc9d2dd066f780e9b3c2ad78 Mon Sep 17 00:00:00 2001 From: Bhawanpreet Lakha Date: Fri, 13 Jul 2018 18:00:06 -0400 Subject: [PATCH] drm/amd/display: Retry link training again [Why] Some receivers seem to fail the first link training but are good on subsequent tries. We want to retry link training again. This fixes HTC vive pro not lighting up after being disabled. [How] Check if the link training passed without fall back if this is not the case then we retry link training. Signed-off-by: Bhawanpreet Lakha Reviewed-by: Harry Wentland Acked-by: Bhawanpreet Lakha Signed-off-by: Alex Deucher --- drivers/gpu/drm/amd/display/dc/core/dc_link.c | 20 +++++++++++++++++-- .../gpu/drm/amd/display/dc/core/dc_link_dp.c | 5 ++++- .../gpu/drm/amd/display/dc/inc/dc_link_dp.h | 3 ++- 3 files changed, 24 insertions(+), 4 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 388a0635c38d..966d2f9c8c99 100644 --- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c +++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c @@ -60,7 +60,14 @@ enum { LINK_RATE_REF_FREQ_IN_MHZ = 27, - PEAK_FACTOR_X1000 = 1006 + PEAK_FACTOR_X1000 = 1006, + /* + * Some receivers fail to train on first try and are good + * on subsequent tries. 2 retries should be plenty. If we + * don't have a successful training then we don't expect to + * ever get one. + */ + LINK_TRAINING_MAX_VERIFY_RETRY = 2 }; /******************************************************************************* @@ -760,7 +767,16 @@ bool dc_link_detect(struct dc_link *link, enum dc_detect_reason reason) */ /* deal with non-mst cases */ - dp_verify_link_cap(link, &link->reported_link_cap); + for (i = 0; i < LINK_TRAINING_MAX_VERIFY_RETRY; i++) { + int fail_count = 0; + + dp_verify_link_cap(link, + &link->reported_link_cap, + &fail_count); + + if (fail_count == 0) + break; + } } /* HDMI-DVI Dongle */ 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 9d901ca70588..58ee9aad13fb 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 @@ -1088,7 +1088,8 @@ static struct dc_link_settings get_max_link_cap(struct dc_link *link) bool dp_verify_link_cap( struct dc_link *link, - struct dc_link_settings *known_limit_link_setting) + struct dc_link_settings *known_limit_link_setting, + int *fail_count) { struct dc_link_settings max_link_cap = {0}; struct dc_link_settings cur_link_setting = {0}; @@ -1160,6 +1161,8 @@ bool dp_verify_link_cap( skip_video_pattern); if (status == LINK_TRAINING_SUCCESS) success = true; + else + (*fail_count)++; } if (success) 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 697b5ee73845..a37255c757e0 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 @@ -35,7 +35,8 @@ struct dc_link_settings; bool dp_verify_link_cap( struct dc_link *link, - struct dc_link_settings *known_limit_link_setting); + struct dc_link_settings *known_limit_link_setting, + int *fail_count); bool dp_validate_mode_timing( struct dc_link *link, -- 2.30.2