On Tue, 21 Sep 2010 16:43:12 -0500 Timur Tabi <[email protected]> wrote:
> On Tue, Sep 21, 2010 at 4:34 PM, Scott Wood <[email protected]> wrote: > > > This doesn't control allocation (it probably should with > > dma_alloc_coherent, though I don't see it in the code), it controls > > whether swiotlb will create a bounce buffer -- defeating the point of > > using DMA to accelerate a memcpy. > > But it would do that only for the 'dev' used in the dma_set_mask() > call. That dev is only used here: > > chan->desc_pool = dma_pool_create("fsl_dma_engine_desc_pool", > chan->dev, > sizeof(struct fsl_desc_sw), > __alignof__(struct fsl_desc_sw), 0); > > Since we don't DMA the descriptors themselves, I just don't see how > this patch does anything. Look in dmaengine.c, there are calls to dma_map_single() and dma_map_page(), using what I assume is that same device pointer -- unless there's confusion between the channel and the controller. -Scott _______________________________________________ Linuxppc-dev mailing list [email protected] https://lists.ozlabs.org/listinfo/linuxppc-dev
