[PATCH AUTOSEL 5.4 006/130] drm/amd/display: Do not silently accept DCC for multiplane formats.

[Kazlauskas, Nicholas]

On 2020-12-29 9:54 a.m., Deucher, Alexander wrote:
> [AMD Public Use]
> 
> 
> I don't know if these fixes related to modifiers make sense in the 
> pre-modifier code base.  Bas, Nick?
> 
> Alex

Mesa should be the only userspace trying to make use of DCC and it 
doesn't do it for video formats. From the kernel side of things we've 
also never supported this and you'd get corruption on the screen if you 
tried.

It's a "fix" for both pre-modifiers and post-modifiers code.

Regards,
Nicholas Kazlauskas

> ------------------------------------------------------------------------
> *From:* amd-gfx <amd-gfx-bounces at lists.freedesktop.org> on behalf of 
> Sasha Levin <sashal at kernel.org>
> *Sent:* Tuesday, December 22, 2020 9:16 PM
> *To:* linux-kernel at vger.kernel.org <linux-kernel at vger.kernel.org>; 
> stable at vger.kernel.org <stable at vger.kernel.org>
> *Cc:* Sasha Levin <sashal at kernel.org>; dri-devel at lists.freedesktop.org 
> <dri-devel at lists.freedesktop.org>; amd-gfx at lists.freedesktop.org 
> <amd-gfx at lists.freedesktop.org>; Bas Nieuwenhuizen 
> <bas at basnieuwenhuizen.nl>; Deucher, Alexander 
> <Alexander.Deucher at amd.com>; Kazlauskas, Nicholas 
> <Nicholas.Kazlauskas at amd.com>
> *Subject:* [PATCH AUTOSEL 5.4 006/130] drm/amd/display: Do not silently 
> accept DCC for multiplane formats.
> From: Bas Nieuwenhuizen <bas at basnieuwenhuizen.nl>
> 
> [ Upstream commit b35ce7b364ec80b54f48a8fdf9fb74667774d2da ]
> 
> Silently accepting it could result in corruption.
> 
> Signed-off-by: Bas Nieuwenhuizen <bas at basnieuwenhuizen.nl>
> Reviewed-by: Alex Deucher <alexander.deucher at amd.com>
> Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas at amd.com>
> Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
> Signed-off-by: Sasha Levin <sashal at kernel.org>
> ---
>   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c 
> b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> index d2dd387c95d86..ce70c42a2c3ec 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -2734,7 +2734,7 @@ fill_plane_dcc_attributes(struct amdgpu_device *adev,
>                   return 0;
> 
>           if (format >= SURFACE_PIXEL_FORMAT_VIDEO_BEGIN)
> -               return 0;
> +               return -EINVAL;
> 
>           if (!dc->cap_funcs.get_dcc_compression_cap)
>                   return -EINVAL;
> -- 
> 2.27.0
> 
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