[PATCH] drm/radeon/kms: consolidate GART code, fix memory fault after GPU lockup

[Michel Dänzer]

[ Dropping stable at kernel.org from CC, it'll get picked up for stable
once it hits mainline ]

On Don, 2011-10-13 at 16:38 -0400, j.glisse at gmail.com wrote: 
> From: Jerome Glisse <jglisse at redhat.com>
> 
> After GPU lockup VRAM gart table is unpinned and thus its pointer
> becomes unvalid. This patch move the unpin code to a common helper
> function and set pointer to NULL so that page update code can check
> if it should update GPU page table or not. That way bo still bound
> to GART can be unbound (pci_unmap_page for all there page) properly
> while there is no need to update the GPU page table.
> 
> Signed-off-by: Jerome Glisse <jglisse at redhat.com>

[...]

> 			rdev->gart.pages_addr[p] = rdev->dummy_page.addr;
>  			page_base = rdev->gart.pages_addr[p];
>  			for (j = 0; j < (PAGE_SIZE / RADEON_GPU_PAGE_SIZE); j++, t++) {
> -				radeon_gart_set_page(rdev, t, page_base);
> +				if (rdev->gart.ptr) {
> +					radeon_gart_set_page(rdev, t, page_base);
> +				}
>  				page_base += RADEON_GPU_PAGE_SIZE;
>  			}
>  		}
> @@ -201,7 +211,9 @@ int radeon_gart_bind(struct radeon_device *rdev, unsigned offset,
>  		rdev->gart.pages[p] = pagelist[i];
>  		page_base = rdev->gart.pages_addr[p];
>  		for (j = 0; j < (PAGE_SIZE / RADEON_GPU_PAGE_SIZE); j++, t++) {
> -			radeon_gart_set_page(rdev, t, page_base);
> +			if (rdev->gart.ptr) {
> +				radeon_gart_set_page(rdev, t, page_base);
> +			}
>  			page_base += RADEON_GPU_PAGE_SIZE;
>  		}
>  	}

Looks like these two loops could be completely guarded by if (rdev->gart.ptr).


> @@ -218,7 +230,9 @@ void radeon_gart_restore(struct radeon_device *rdev)
>  	for (i = 0, t = 0; i < rdev->gart.num_cpu_pages; i++) {
>  		page_base = rdev->gart.pages_addr[i];
>  		for (j = 0; j < (PAGE_SIZE / RADEON_GPU_PAGE_SIZE); j++, t++) {
> -			radeon_gart_set_page(rdev, t, page_base);
> +			if (rdev->gart.ptr) {
> +				radeon_gart_set_page(rdev, t, page_base);
> +			}
>  			page_base += RADEON_GPU_PAGE_SIZE;
>  		}
>  	}

I think this should rather BUG_ON(!rdev->gart.ptr).


Looks good to me otherwise.


-- 
Earthling Michel Dänzer           |                   http://www.amd.com
Libre software enthusiast         |          Debian, X and DRI developer