Re: [Intel-gfx] [PATCH 2/2] drm/i915/dmabuf: drop the flush on discrete

["Thomas Hellström" <thomas.hellstrom@linux.intel.com>]

Hi, Matt

On 10/21/21 14:53, Matthew Auld wrote:
> We were overzealous here; even though discrete is non-LLC, it should
> still be always coherent.
>
> Signed-off-by: Matthew Auld <matthew.auld@intel.com>
> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
> ---
>   drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
> index a45d0ec2c5b6..848e81368043 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
> @@ -251,7 +251,8 @@ static int i915_gem_object_get_pages_dmabuf(struct drm_i915_gem_object *obj)
>   		return PTR_ERR(pages);
>   
>   	/* XXX: consider doing a vmap flush or something */
> -	if (!HAS_LLC(i915) || i915_gem_object_can_bypass_llc(obj))
> +	if ((!HAS_LLC(i915) && !IS_DGFX(i915)) ||

Q: I notice that DG1 at least has HAS_SNOOP. Would it be incorrect to 
use that in this case?

/Thomas



> +	    i915_gem_object_can_bypass_llc(obj))
>   		wbinvd_on_all_cpus();
>   
>   	sg_page_sizes = i915_sg_dma_sizes(pages->sgl);