On Mon, 2008-02-25 at 17:54 -0500, Jeff Garzik wrote: > Matthew Wilcox wrote: > > On Mon, Feb 25, 2008 at 11:40:35PM +0100, Andi Kleen wrote: > >>> (I must have fixed it somehow because it works on parisc, which is most > >>> unforgiving of drivers which do DMA without the DMA API). > >> At least on x86 the DMA API cannot do ISA bouncing. > > > > You're saying that if I set a 24-bit DMA mask, and then do a > > pci_alloc_coherent(), x86 might hand me back something that's not > > accessible? That would be just broken. > > Indeed. It's doing the right thing (from pci-dma_32.c): void *dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_handle, gfp_t gfp) [...] if (dev == NULL || (dev->coherent_dma_mask < 0xffffffff)) gfp |= GFP_DMA; ret = (void *)__get_free_pages(gfp, order); Which correctly allocates the region. James - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
