linux-kernel - Re: [PATCH] Revert duplicate "drm/amdgpu: disable peer-to-peer access for DCC-enabled GC12 VRAM surfaces"

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Message-ID: <CADnq5_Nqq6sXH22utE6=-xAD1Fm8K6vmQ1hfFyvjwB-uX7UcMg@mail.gmail.com>
Date: Thu, 8 Jan 2026 15:08:15 -0500
From: Alex Deucher <alexdeucher@...il.com>
To: Peter Colberg <pcolberg@...hat.com>
Cc: Alex Deucher <alexander.deucher@....com>, 
	Christian König <christian.koenig@....com>, 
	David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>, Dave Airlie <airlied@...hat.com>, 
	amd-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Revert duplicate "drm/amdgpu: disable peer-to-peer access
 for DCC-enabled GC12 VRAM surfaces"

On Mon, Dec 22, 2025 at 12:51 PM Peter Colberg <pcolberg@...hat.com> wrote:
>
> This reverts commit 22a36e660d014925114feb09a2680bb3c2d1e279 once,
> which was merged twice due to an incorrect backmerge resolution.
>
> Fixes: ce0478b02ed2 ("Merge tag 'v6.18-rc6' into drm-next")
> Signed-off-by: Peter Colberg <pcolberg@...hat.com>

Applied.  Thanks!

Alex

> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c | 12 ------------
>  1 file changed, 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
> index e22cfa7c6d32f286de94c6e0947c20db41894b68..c1461317eb29877446e69562a58e17a77203a79e 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
> @@ -83,18 +83,6 @@ static int amdgpu_dma_buf_attach(struct dma_buf *dmabuf,
>         struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
>         int r;
>
> -       /*
> -        * Disable peer-to-peer access for DCC-enabled VRAM surfaces on GFX12+.
> -        * Such buffers cannot be safely accessed over P2P due to device-local
> -        * compression metadata. Fallback to system-memory path instead.
> -        * Device supports GFX12 (GC 12.x or newer)
> -        * BO was created with the AMDGPU_GEM_CREATE_GFX12_DCC flag
> -        *
> -        */
> -       if (amdgpu_ip_version(adev, GC_HWIP, 0) >= IP_VERSION(12, 0, 0) &&
> -           bo->flags & AMDGPU_GEM_CREATE_GFX12_DCC)
> -               attach->peer2peer = false;
> -
>         /*
>          * Disable peer-to-peer access for DCC-enabled VRAM surfaces on GFX12+.
>          * Such buffers cannot be safely accessed over P2P due to device-local
>
> ---
> base-commit: 9448598b22c50c8a5bb77a9103e2d49f134c9578
> change-id: 20251222-fix-duplicate-amdgpu-44017b1535eb
>
> Best regards,
> --
> Peter Colberg <pcolberg@...hat.com>
>