On 2018-07-13 01:40 PM, Bhawanpreet Lakha wrote:
> Some receivers seem to fail the first link training but are good on
> subsequent tries. Check if the max setting was good otherwise retry
> link training.
>
> This fixes HTC vive pro issue where it would fail to light up after
> being disabled.
>
> Signed-off-by: Bhawanpreet Lakha <Bhawanpreet.Lakha at amd.com>
Reviewed-by: Harry Wentland <harry.wentland at amd.com>
Harry
> ---
> drivers/gpu/drm/amd/display/dc/core/dc_link.c | 21 +++++++++++++++++++--
> drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 9 ++++++---
> drivers/gpu/drm/amd/display/dc/inc/dc_link_dp.h | 3 ++-
> 3 files changed, 27 insertions(+), 6 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 4de68fa074a0..34ab1a91baab 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 +767,17 @@ bool dc_link_detect(struct dc_link *link, enum dc_detect_reason reason)
> */
>
> /* deal with non-mst cases */
> - dp_hbr_verify_link_cap(link, &link->reported_link_cap);
> + for (i = 0; i < LINK_TRAINING_MAX_VERIFY_RETRY; i++) {
> + int fail_count = 0;
> +
> + dp_hbr_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 8fbb999e4a8a..18258944f442 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_hbr_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};
> @@ -1146,15 +1147,17 @@ bool dp_hbr_verify_link_cap(
> cur);
>
>
> - if (skip_link_training)
> + if (skip_link_training) {
> success = true;
> - else {
> + } else {
> status = dc_link_dp_perform_link_training(
> link,
> cur,
> 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 2f783c650084..5eed19153de5 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_hbr_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,
>
