Re: [Intel-gfx] [PATCH v2 3/6] drm/ttm: clear the ttm_tt when bo->resource is NULL

["Das, Nirmoy" <nirmoy.das@linux.intel.com>]

On 1/30/2023 1:06 PM, Matthew Auld wrote:
> In the next few patches, when initially creating a ttm BO, the
> bo->resource is NULL, and the driver is then expected to handle the
> initial dummy move.  However, if this is created as a system resource
> the first ttm_tt we create will always have the clear value set to
> false. Previously the initial ttm_tt would be created in
> ttm_bo_validate() with the clear parameter always set to true.
>
> Signed-off-by: Matthew Auld <matthew.auld@intel.com>
> Cc: Christian König <ckoenig.leichtzumerken@gmail.com>
> Reviewed-by: Christian König <ckoenig.leichtzumerken@gmail.com>
Acked-by: Nirmoy Das <nirmoy.das@intel.com>
> ---
>   drivers/gpu/drm/ttm/ttm_bo.c | 3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
> index 326a3d13a829..773080f48864 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> @@ -120,8 +120,7 @@ static int ttm_bo_handle_move_mem(struct ttm_buffer_object *bo,
>   	bool old_use_tt, new_use_tt;
>   	int ret;
>   
> -	old_use_tt = bo->resource &&
> -		ttm_manager_type(bdev, bo->resource->mem_type)->use_tt;
> +	old_use_tt = !bo->resource || ttm_manager_type(bdev, bo->resource->mem_type)->use_tt;
>   	new_use_tt = ttm_manager_type(bdev, mem->mem_type)->use_tt;
>   
>   	ttm_bo_unmap_virtual(bo);