Re: [PATCH 3/4] drm/nouveau: hook up cache sync functions

[Lucas Stach]

Am Montag, den 19.05.2014, 10:46 +0200 schrieb Thierry Reding:
> On Mon, May 19, 2014 at 04:10:57PM +0900, Alexandre Courbot wrote:
> > From: Lucas Stach <dev@xxxxxxxxxx>
> > 
> > Signed-off-by: Lucas Stach <dev@xxxxxxxxxx>
> > [acourbot@xxxxxxxxxx: make conditional and platform-friendly]
> > Signed-off-by: Alexandre Courbot <acourbot@xxxxxxxxxx>
> 
> Perhaps having a propery commit message here would be good.
> 
> > diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c b/drivers/gpu/drm/nouveau/nouveau_bo.c
> [...]
> > +#ifdef NOUVEAU_NEED_CACHE_SYNC
> > +void
> > +nouveau_bo_sync_for_cpu(struct nouveau_bo *nvbo)
> > +{
> > +	struct nouveau_device *device;
> > +	struct ttm_tt *ttm = nvbo->bo.ttm;
> > +
> > +	device = nouveau_dev(nouveau_bdev(ttm->bdev)->dev);
> > +
> > +	if (nvbo->bo.ttm && nvbo->bo.ttm->caching_state == tt_cached)
> > +		ttm_dma_tt_cache_sync_for_cpu((struct ttm_dma_tt *)nvbo->bo.ttm,
> > +					      nv_device_base(device));
> 
> Can we be certain at this point that the struct ttm_tt is in fact a
> struct ttm_dma_tt?

Yes, for all cases except AGP, where things are mapped WC anyways (so
caching_state is always != cached) nouveau_bo_driver uses
nouveau_ttm_tt_create() as its ttm_tt_create callback. This in turn
calls nouveau_sgdma_create_ttm() which uses ttm_dma_tt_init()
unconditionally.

Regards,
Lucas
-- 
Pengutronix e.K.             | Lucas Stach                 |
Industrial Linux Solutions   | http://www.pengutronix.de/  |

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