[PATCH] drm/amdgpu: Add DCC GFX12 flag to enable address alignment

[Christian König]

Am 05.08.24 um 16:01 schrieb Arunpravin Paneer Selvam:
> We require this flag AMDGPU_GEM_CREATE_GFX12_DCC or any other
> kernel level GFX12 DCC flag to differentiate the DCC buffers and other
> pinned display buffers(which has TTM_PL_FLAG_CONTIGUOUS enabled).

That's a pretty bad idea, the DCC flag is not the right approach to 
differentiate this.

What other pinned display buffers are you talking about? As far as I can 
see that patch shouldn't be necessary in any way.

Regards,
Christian.

>
> If we use the TTM_PL_FLAG_CONTIGUOUS flag for DCC buffers, we may over
> allocate for all the pinned display buffers unnecessarily that leads to
> memory allocation failure.
>
> Signed-off-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam at amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> index 5415a5cc7789..7de0ac07a060 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> @@ -509,7 +509,8 @@ static int amdgpu_vram_mgr_new(struct ttm_resource_manager *man,
>   		/* Allocate blocks in desired range */
>   		vres->flags |= DRM_BUDDY_RANGE_ALLOCATION;
>   
> -	if (adev->gmc.gmc_funcs->get_dcc_alignment)
> +	if (bo->flags & AMDGPU_GEM_CREATE_GFX12_DCC &&
> +	    adev->gmc.gmc_funcs->get_dcc_alignment)
>   		adjust_dcc_size = amdgpu_gmc_get_dcc_alignment(adev);
>   
>   	remaining_size = (u64)vres->base.size;