[PATCH 1/4] drm/ttm: add TTM_PL_FLAG_TEMPORARY flag v3

[Christian König]

Thomas any comments on this?

Is the purpose of this now clear enough?

Thanks,
Christian.

Am 01.06.21 um 14:25 schrieb Christian König:
> From: Lang Yu <Lang.Yu at amd.com>
>
> Sometimes drivers need to use bounce buffers to evict BOs. While those reside
> in some domain they are not necessarily suitable for CS.
>
> Add a flag so that drivers can note that a bounce buffers needs to be
> reallocated during validation.
>
> v2: add detailed comments
> v3 (chk): merge commits and rework commit message
>
> Suggested-by: Christian König <christian.koenig at amd.com>
> Signed-off-by: Lang Yu <Lang.Yu at amd.com>
> Signed-off-by: Christian König <christian.koenig at amd.com>
> ---
>   drivers/gpu/drm/ttm/ttm_bo.c    | 3 +++
>   include/drm/ttm/ttm_placement.h | 7 +++++--
>   2 files changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
> index 51a94fd63bd7..6b393502198e 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> @@ -929,6 +929,9 @@ static bool ttm_bo_places_compat(const struct ttm_place *places,
>   {
>   	unsigned i;
>   
> +	if (mem->placement & TTM_PL_FLAG_TEMPORARY)
> +		return false;
> +
>   	for (i = 0; i < num_placement; i++) {
>   		const struct ttm_place *heap = &places[i];
>   
> diff --git a/include/drm/ttm/ttm_placement.h b/include/drm/ttm/ttm_placement.h
> index aa6ba4d0cf78..8995c9e4ec1b 100644
> --- a/include/drm/ttm/ttm_placement.h
> +++ b/include/drm/ttm/ttm_placement.h
> @@ -47,8 +47,11 @@
>    * top of the memory area, instead of the bottom.
>    */
>   
> -#define TTM_PL_FLAG_CONTIGUOUS  (1 << 19)
> -#define TTM_PL_FLAG_TOPDOWN     (1 << 22)
> +#define TTM_PL_FLAG_CONTIGUOUS  (1 << 0)
> +#define TTM_PL_FLAG_TOPDOWN     (1 << 1)
> +
> +/* For multihop handling */
> +#define TTM_PL_FLAG_TEMPORARY   (1 << 2)
>   
>   /**
>    * struct ttm_place