drm/amd: Revert "drm/amd/display: keep eDP Vdd on when eDP stream is already enabled"

[Mark Pearson]

On 6/15/22 18:30, Mario Limonciello wrote:
> A variety of Lenovo machines with Rembrandt APUs and OLED panels have
> stopped showing the display at login.  This behavior clears up after
> leaving it idle and moving the mouse or touching keyboard.
> 
> It was bisected to be caused by commit 559e2655220d ("drm/amd/display:
> keep eDP Vdd on when eDP stream is already enabled").  Revert this commit
> to fix the issue.
> 
> Link: https://gitlab.freedesktop.org/drm/amd/-/issues/2047
> Reported-by: Aaron Ma <aaron.ma at canonical.com>
> Fixes: 559e2655220d ("drm/amd/display: keep eDP Vdd on when eDP stream is already enabled")
> Signed-off-by: Mario Limonciello <mario.limonciello at amd.com>
> ---
>  .../display/dc/dce110/dce110_hw_sequencer.c   | 24 ++-----------------
>  1 file changed, 2 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c b/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c
> index 7eff7811769d..5f2afa5b4814 100644
> --- a/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c
> +++ b/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c
> @@ -1766,29 +1766,9 @@ void dce110_enable_accelerated_mode(struct dc *dc, struct dc_state *context)
>  				break;
>  			}
>  		}
> -
> -		/*
> -		 * TO-DO: So far the code logic below only addresses single eDP case.
> -		 * For dual eDP case, there are a few things that need to be
> -		 * implemented first:
> -		 *
> -		 * 1. Change the fastboot logic above, so eDP link[0 or 1]'s
> -		 * stream[0 or 1] will all be checked.
> -		 *
> -		 * 2. Change keep_edp_vdd_on to an array, and maintain keep_edp_vdd_on
> -		 * for each eDP.
> -		 *
> -		 * Once above 2 things are completed, we can then change the logic below
> -		 * correspondingly, so dual eDP case will be fully covered.
> -		 */
> -
> -		// We are trying to enable eDP, don't power down VDD if eDP stream is existing
> -		if ((edp_stream_num == 1 && edp_streams[0] != NULL) || can_apply_edp_fast_boot) {
> +		// We are trying to enable eDP, don't power down VDD
> +		if (can_apply_edp_fast_boot)
>  			keep_edp_vdd_on = true;
> -			DC_LOG_EVENT_LINK_TRAINING("Keep eDP Vdd on\n");
> -		} else {
> -			DC_LOG_EVENT_LINK_TRAINING("No eDP stream enabled, turn eDP Vdd off\n");
> -		}
>  	}
>  
>  	// Check seamless boot support

Verified this fixed the issue on my Lenovo Z13 (R5 Pro 6650U) when
applied to a build of 5.18 from Linus's tree
Thanks Mario!

Tested-by: markpearson at lenovo.com