Quoting Kuogee Hsieh (2020-10-20 09:59:59)
> No need to check LINK_STATuS_UPDATED bit before
LINK_STATUS_UPDATED?
> return 6 bytes of link status during link training.
Why?
> This patch also fix phy compliance test link rate
> conversion error.
How?
>
> Signed-off-by: Kuogee Hsieh <khsieh@xxxxxxxxxxxxxx>
> ---
Any Fixes: tag?
> drivers/gpu/drm/msm/dp/dp_ctrl.c | 20 ++++++--------------
> drivers/gpu/drm/msm/dp/dp_link.c | 24 +++++++++++-------------
> 2 files changed, 17 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
> index 6bdaec778c4c..76e891c91c6e 100644
> --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
> +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
> @@ -1061,23 +1061,15 @@ static bool dp_ctrl_train_pattern_set(struct dp_ctrl_private *ctrl,
> static int dp_ctrl_read_link_status(struct dp_ctrl_private *ctrl,
> u8 *link_status)
> {
> - int len = 0;
> - u32 const offset = DP_LANE_ALIGN_STATUS_UPDATED - DP_LANE0_1_STATUS;
> - u32 link_status_read_max_retries = 100;
> -
> - while (--link_status_read_max_retries) {
> - len = drm_dp_dpcd_read_link_status(ctrl->aux,
> - link_status);
> - if (len != DP_LINK_STATUS_SIZE) {
> - DRM_ERROR("DP link status read failed, err: %d\n", len);
> - return len;
> - }
> + int ret = 0, len;
>
> - if (!(link_status[offset] & DP_LINK_STATUS_UPDATED))
> - return 0;
> + len = drm_dp_dpcd_read_link_status(ctrl->aux, link_status);
> + if (len != DP_LINK_STATUS_SIZE) {
> + DRM_ERROR("DP link status read failed, err: %d\n", len);
> + ret = len;
Could this be positive if the len is greater than 0 but not
DP_LINK_STATUS_SIZE? Maybe the check should be len < 0? We certainly
don't want to return some smaller size from this function, right?
> }
>
> - return -ETIMEDOUT;
> + return ret;
> }
>
> static int dp_ctrl_link_train_1(struct dp_ctrl_private *ctrl,
> diff --git a/drivers/gpu/drm/msm/dp/dp_link.c b/drivers/gpu/drm/msm/dp/dp_link.c
> index c811da515fb3..58d65daae3b3 100644
> --- a/drivers/gpu/drm/msm/dp/dp_link.c
> +++ b/drivers/gpu/drm/msm/dp/dp_link.c
> @@ -773,7 +773,8 @@ static int dp_link_process_link_training_request(struct dp_link_private *link)
> link->request.test_lane_count);
>
> link->dp_link.link_params.num_lanes = link->request.test_lane_count;
> - link->dp_link.link_params.rate = link->request.test_link_rate;
> + link->dp_link.link_params.rate =
> + drm_dp_bw_code_to_link_rate(link->request.test_link_rate);
Why are we storing bw_code in test_link_rate? This looks very confusing.
>
> return 0;
> }
