[PATCH] Revert "drm/amd/display: limit clear_update_flags to dcn32 and above"

[Limonciello, Mario]

On 7/17/25 9:36 AM, Melissa Wen wrote:
> This reverts commit e1bd5e0bb4ca0d633ad698abd3658f8265009b81.
> 
> The commit causes a regression in Steam Deck (DCN 3.01), reintroducing a
> functional issue reported in [1] that was fixed by calling the
> clear_update_flags() from commit 7671f62c10f2a.
> 
> On Steam Deck, we use multiple hw plane color caps and up to two overlay
> planes with dynamic pipe split policy. I.e. with 1 primary + 1 overlay,
> the driver split planes into two (with 4 pipes), but with 1 primary + 2
> overlays, we don't have enough pipe for splitting. Glitches appear in
> this pipe-split transition of 1-2 overlay planes, if the driver doesn't
> clear update flags.
> 
> Besides that, the issue the commit e1bd5e0bb4ca tries to address [2]
> isn't functional.
> 
> Link: https://gitlab.freedesktop.org/drm/amd/-/issues/3441 [1]
> Link: https://gitlab.freedesktop.org/drm/amd/-/issues/4129 [2]
> Signed-off-by: Melissa Wen <mwen at igalia.com>

Can you please double check the use case that prompted 
e1bd5e0bb4ca0d633ad698abd3658f8265009b81 in the first place?  IE With 
this revert you proposed do you see a traceback on unplug of external 
display?

> ---
>   drivers/gpu/drm/amd/display/dc/core/dc.c | 5 +++--
>   1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/display/dc/core/dc.c b/drivers/gpu/drm/amd/display/dc/core/dc.c
> index c31f7f8e409f..7c48f72e5917 100644
> --- a/drivers/gpu/drm/amd/display/dc/core/dc.c
> +++ b/drivers/gpu/drm/amd/display/dc/core/dc.c
> @@ -5443,7 +5443,8 @@ bool dc_update_planes_and_stream(struct dc *dc,
>   	else
>   		ret = update_planes_and_stream_v2(dc, srf_updates,
>   			surface_count, stream, stream_update);
> -	if (ret && dc->ctx->dce_version >= DCN_VERSION_3_2)
> +
> +	if (ret)
>   		clear_update_flags(srf_updates, surface_count, stream);
>   
>   	return ret;
> @@ -5474,7 +5475,7 @@ void dc_commit_updates_for_stream(struct dc *dc,
>   		ret = update_planes_and_stream_v1(dc, srf_updates, surface_count, stream,
>   				stream_update, state);
>   
> -	if (ret && dc->ctx->dce_version >= DCN_VERSION_3_2)
> +	if (ret)
>   		clear_update_flags(srf_updates, surface_count, stream);
>   }
>