Re: [PATCH 1/5] drm/amdgpu: Respect placement requirements in amdgpu_gtt_mgr functions

["Christian König" <christian.koenig@amd.com>]

On 5/19/26 10:22, Timur Kristóf wrote:
> When testing intersection and compatibility, respect
> the actual placement requirements. This is a pre-requisite
> for ensuring that UVD CS BOs do not cross 256M segments.
> 
> Fixes: ded910f368a5 ("drm/amdgpu: Implement intersect/compatible functions")
> Suggested-by: Christian König <christian.koenig@amd.com>
> Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>

Reviewed-by: Christian König <christian.koenig@amd.com>

> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_gtt_mgr.c | 30 +++++++++++++++++++--
>  1 file changed, 28 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gtt_mgr.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gtt_mgr.c
> index 02f85802f579..19b6770a877d 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gtt_mgr.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gtt_mgr.c
> @@ -272,7 +272,20 @@ static bool amdgpu_gtt_mgr_intersects(struct ttm_resource_manager *man,
>  				      const struct ttm_place *place,
>  				      size_t size)
>  {
> -	return !place->lpfn || amdgpu_gtt_mgr_has_gart_addr(res);
> +	const struct drm_mm_node *const node = &to_ttm_range_mgr_node(res)->mm_nodes[0];
> +	const u32 num_pages = PFN_UP(size);
> +
> +	if (!place->lpfn)
> +		return true;
> +
> +	if (!amdgpu_gtt_mgr_has_gart_addr(res))
> +		return false;
> +
> +	if (place->fpfn >= (node->start + num_pages) ||
> +	    (place->lpfn && place->lpfn <= node->start))
> +		return false;
> +
> +	return true;
>  }
>  
>  /**
> @@ -290,7 +303,20 @@ static bool amdgpu_gtt_mgr_compatible(struct ttm_resource_manager *man,
>  				      const struct ttm_place *place,
>  				      size_t size)
>  {
> -	return !place->lpfn || amdgpu_gtt_mgr_has_gart_addr(res);
> +	const struct drm_mm_node *const node = &to_ttm_range_mgr_node(res)->mm_nodes[0];
> +	const u32 num_pages = PFN_UP(size);
> +
> +	if (!place->lpfn)
> +		return true;
> +
> +	if (!amdgpu_gtt_mgr_has_gart_addr(res))
> +		return false;
> +
> +	if (node->start < place->fpfn ||
> +	    (place->lpfn && (node->start + num_pages) > place->lpfn))
> +		return false;
> +
> +	return true;
>  }
>  
>  /**