Re: [PATCH] drm/prime: skip CPU sync in map/unmap dma_buf

2017-11-30 Thread Daniel Vetter
On Thu, Nov 30, 2017 at 08:56:42PM +, Chris Wilson wrote: > Quoting Lucas Stach (2017-11-30 17:34:28) > > Dma-bufs should already be device coherent, as they are only pulled in the > > CPU domain via the begin/end cpu_access calls. As we cache the mapping set > > up by dma_map_sg a CPU sync at

Re: [PATCH] drm/prime: skip CPU sync in map/unmap dma_buf

2017-11-30 Thread Chris Wilson
Quoting Lucas Stach (2017-11-30 17:34:28) > Dma-bufs should already be device coherent, as they are only pulled in the > CPU domain via the begin/end cpu_access calls. As we cache the mapping set > up by dma_map_sg a CPU sync at this point will not actually guarantee proper > coherency on non-coher

[PATCH] drm/prime: skip CPU sync in map/unmap dma_buf

2017-11-30 Thread Lucas Stach
Dma-bufs should already be device coherent, as they are only pulled in the CPU domain via the begin/end cpu_access calls. As we cache the mapping set up by dma_map_sg a CPU sync at this point will not actually guarantee proper coherency on non-coherent architectures, so we can as well stop pretendi