[PATCH] drm/radeon: Don't flush the GART TLB if rdev->gart.ptr == NULL

[Christian König]

On 03.07.2015 03:02, Michel Dänzer wrote:
> From: Michel Dänzer <michel.daenzer at amd.com>
>
> This can be the case when the GPU is powered off, e.g. via vgaswitcheroo
> or runpm. When the GPU is powered up again, radeon_gart_table_vram_pin
> flushes the TLB after setting rdev->gart.ptr to non-NULL.
>
> Fixes panic on powering off R7xx GPUs.
>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=61529
> Signed-off-by: Michel Dänzer <michel.daenzer at amd.com>

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

> ---
>   drivers/gpu/drm/radeon/radeon_gart.c | 12 ++++++++----
>   1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/radeon/radeon_gart.c 
> b/drivers/gpu/drm/radeon/radeon_gart.c
> index 5450fa9..c4777c8 100644
> --- a/drivers/gpu/drm/radeon/radeon_gart.c
> +++ b/drivers/gpu/drm/radeon/radeon_gart.c
> @@ -260,8 +260,10 @@ void radeon_gart_unbind(struct radeon_device *rdev, 
> unsigned offset,
>                       }
>               }
>       }
> -     mb();
> -     radeon_gart_tlb_flush(rdev);
> +     if (rdev->gart.ptr) {
> +             mb();
> +             radeon_gart_tlb_flush(rdev);
> +     }
>   }
>   
>   /**
> @@ -306,8 +308,10 @@ int radeon_gart_bind(struct radeon_device *rdev, 
> unsigned offset,
>                       page_base += RADEON_GPU_PAGE_SIZE;
>               }
>       }
> -     mb();
> -     radeon_gart_tlb_flush(rdev);
> +     if (rdev->gart.ptr) {
> +             mb();
> +             radeon_gart_tlb_flush(rdev);
> +     }
>       return 0;
>   }
>