Re: [PATCH] drm/ttm: Make sure BOs being swapped out are cacheable

[Christian KÃnig]

Am 25.01.2017 um 10:25 schrieb Thomas Hellstrom:
> On 01/25/2017 09:21 AM, Michel DÃnzer wrote:
> > From: Michel DÃnzer <michel.daenzer@xxxxxxx>
> >
> > The current caching state may not be tt_cached, even though the
> > placement contains TTM_PL_FLAG_CACHED, because placement can contain
> > multiple caching flags. Trying to swap out such a BO would trip up the
> >
> > 	BUG_ON(ttm->caching_state != tt_cached);
> >
> > in ttm_tt_swapout.
> >
> > Cc: stable@xxxxxxxxxxxxxxx
> > Signed-off-by: Michel DÃnzer <michel.daenzer@xxxxxxx>
> Reviewed-by: Thomas Hellstrom <thellstrom@xxxxxxxxxx>

Reviewed-by: Christian KÃnig <christian.koenig@xxxxxxx>.

> > ---
> >   drivers/gpu/drm/ttm/ttm_bo.c | 4 ++--
> >   1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
> > index d5063618efa7..86e3b233b722 100644
> > --- a/drivers/gpu/drm/ttm/ttm_bo.c
> > +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> > @@ -1670,7 +1670,6 @@ static int ttm_bo_swapout(struct ttm_mem_shrink *shrink)
> >   	struct ttm_buffer_object *bo;
> >   	int ret = -EBUSY;
> >   	int put_count;
> > -	uint32_t swap_placement = (TTM_PL_FLAG_CACHED | TTM_PL_FLAG_SYSTEM);
> >   
> >   	spin_lock(&glob->lru_lock);
> >   	list_for_each_entry(bo, &glob->swap_lru, swap) {
> > @@ -1701,7 +1700,8 @@ static int ttm_bo_swapout(struct ttm_mem_shrink *shrink)
> >   	 * Move to system cached
> >   	 */
> >   
> > -	if ((bo->mem.placement & swap_placement) != swap_placement) {
> > +	if (bo->mem.mem_type != TTM_PL_SYSTEM ||
> > +	    bo->ttm->caching_state != tt_cached) {
> >   		struct ttm_mem_reg evict_mem;
> >   
> >   		evict_mem = bo->mem;