[PATCH] drm/amd/display: assign fb_location only if bo is pinned

[Andrey Grodzovsky]

On 10/24/2017 09:51 AM, S, Shirish wrote:
> From: Shirish S <shirish.s at amd.com>
>
> On some systems amdgpu_bo_gpu_offset seems to be
> called before the BO is pinned, leading to page faults
> as the GPU address is still subject to change.
>
> This patch fixes the above issue.
>
> Signed-off-by: Shirish S <shirish.s at amd.com>
> ---
>   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 7 +++++--
>   1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> index 974ee97..b251b7e 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -1786,8 +1786,11 @@ static int get_fb_info(const struct amdgpu_framebuffer *amdgpu_fb,
>   		return r;
>   	}
>   
> -	if (fb_location)
> -		*fb_location = amdgpu_bo_gpu_offset(rbo);
> +	r = amdgpu_bo_pin(rbo, AMDGPU_GEM_DOMAIN_VRAM, fb_location);
> +	if (unlikely(r != 0)) {
> +		amdgpu_bo_unreserve(rbo);
> +		return -EINVAL;
> +	}

Where the unpin would happen then ? Today DAL calls pin from 
dm_plane_helper_prepare_fb while the unpin from dm_plane_helper_cleanup_fb.

Thanks,
Andrey

>   
>   	if (tiling_flags)
>   		amdgpu_bo_get_tiling_flags(rbo, tiling_flags);