[Intel-gfx] [PATCH 7/8] drm/i915: Mark imported dma-buf objects as being coherent

[Joonas Lahtinen]

On ti, 2016-07-19 at 11:51 +0100, Chris Wilson wrote:
> A foreign dma-buf does not share our cache domain tracking, and we rely
> on the producer ensuring cache coherency. Marking them as being in the
> CPU domain is incorrect.
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>

Maybe even add a comment above the assignment that _GTT is used in the
purpose of being coherent.

Reviewed-by: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>

> ---
>  drivers/gpu/drm/i915/i915_gem_dmabuf.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/i915_gem_dmabuf.c
> index 80bbe43a2e92..c7d734248ed0 100644
> --- a/drivers/gpu/drm/i915/i915_gem_dmabuf.c
> +++ b/drivers/gpu/drm/i915/i915_gem_dmabuf.c
> @@ -299,6 +299,8 @@ struct drm_gem_object *i915_gem_prime_import(struct drm_device *dev,
>  	drm_gem_private_object_init(dev, &obj->base, dma_buf->size);
>  	i915_gem_object_init(obj, &i915_gem_object_dmabuf_ops);
>  	obj->base.import_attach = attach;
> +	obj->base.read_domains = I915_GEM_DOMAIN_GTT;
> +	obj->base.write_domain = 0;
>  
>  	return &obj->base;
>  
-- 
Joonas Lahtinen
Open Source Technology Center
Intel Corporation