[PATCH 2/2] Revert "drm/amd/display: Don't skip link training for empty dongle"

[Harry Wentland]

On 2020-01-23 2:45 p.m., Harry Wentland wrote:
> This reverts commit 80adaebd2d411b7d6872a097634848a71eb13d20.
> 
> [WHY]
> This change was working around a regression that occured in this
> patch:
> 0301ccbaf67d drm/amd/display: DP Compliance 400.1.1 failure
> 
> With the fix to run verify_link_cap when the SINK_COUNT of
> dongles becomes non-zero this change is no longer needed.
> 
> Cc: Louis Li <Ching-shih.Li at amd.com>
> Cc: Wenjing Liu <Wenjing.Liu at amd.com>
> Cc: Hersen Wu <hersenxs.wu at amd.com>
> Cc: Eric Yang <Eric.Yang2 at amd.com>
> Signed-off-by: Harry Wentland <harry.wentland at amd.com>

Both patches have been offline reviewed by Wenjing. I'll merge them with
his review.

Harry

> ---
>  drivers/gpu/drm/amd/display/dc/core/dc_link.c | 10 ++--------
>  1 file changed, 2 insertions(+), 8 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 cc2e05003595..a09119c10d7c 100644
> --- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c
> +++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
> @@ -851,18 +851,12 @@ static bool dc_link_detect_helper(struct dc_link *link,
>  				if (memcmp(&link->dpcd_caps, &prev_dpcd_caps, sizeof(struct dpcd_caps)))
>  					same_dpcd = false;
>  			}
> -			/* Active dongle plug in without display or downstream unplug*/
> +			/* Active dongle downstream unplug*/
>  			if (link->type == dc_connection_active_dongle &&
>  				link->dpcd_caps.sink_count.bits.SINK_COUNT == 0) {
> -				if (prev_sink != NULL) {
> +				if (prev_sink != NULL)
>  					/* Downstream unplug */
>  					dc_sink_release(prev_sink);
> -				} else {
> -					/* Empty dongle plug in */
> -					dp_verify_link_cap_with_retries(link,
> -							&link->reported_link_cap,
> -							LINK_TRAINING_MAX_VERIFY_RETRY);
> -				}
>  				return true;
>  			}
>  
>