Re: [PATCH 1/4] drm/i915: check that the i965g/gm 4G limit is really obeyed

[Damien Lespiau <damien.lespiau@intel.com>]

On Mon, Oct 07, 2013 at 05:15:45PM -0300, Rodrigo Vivi wrote:
> From: Daniel Vetter <daniel.vetter@ffwll.ch>
> 
> In truly crazy circumstances shmem might give us the wrong type of
> page. So be a bit paranoid and double check this.
> 
> Reviewer: Damien Lespiau <damien.lespiau@intel.com>
> Cc: Rob Clark <robdclark@gmail.com>
> References: http://lkml.org/lkml/2011/7/11/238
> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> Signed-off-by: Rodrigo Vivi <rodrigo.vivi@gmail.com>
> ---
>  drivers/gpu/drm/i915/i915_gem.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 19ecfa8..692ebf7 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -1903,6 +1903,9 @@ i915_gem_object_get_pages_gtt(struct drm_i915_gem_object *obj)
>  			sg->length += PAGE_SIZE;
>  		}
>  		last_pfn = page_to_pfn(page);
> +
> +		/* Check that the i965g/gm workaround works. */
> +		WARN_ON((gfp & __GFP_DMA32) && (last_pfn >= 0x00100000UL));

I guess we could have something like last_pfn >= (GB(4) >> PAGE_SHIFT)
but in any case:

Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>

-- 
Damien