On Wed, 31 Jul 2013, Russell King - ARM Linux wrote: > On Wed, Jul 31, 2013 at 08:54:06PM +0100, Stefano Stabellini wrote: > > Initially set dma_ops to arm_dma_ops. > > Use dma_ops instead of arm_dma_ops in dmabounce. > > > > Signed-off-by: Stefano Stabellini <[email protected]> > > CC: [email protected] > > CC: [email protected] > > If you're using swiotlb, there's little point in converting dmabounce > to be able to use it, because it's basically providing the same > functionality - dmabounce is there to do software buffer bouncing within > the DMA to move streaming buffers from DMA-inaccessible memory into > DMA-accessible memory. > > It's original use is with older SoCs with buggy DMA (eg, those which > can only address alternate 1MB chunks of memory for example) but also > got used in situations where alternative solutions would've been better > (like using swiotlb.) I've been discouraging its use as it's suffered > from memory exhaustion problems (there's a number of threads and bug > reports which were never solved about IXP4xx(?) platforms suffering > this due to this bouncing.)
OK, I'll let dmabounce keep using arm_dma_ops directly (instead of dma_ops). Should I add "depends on !DMABOUNCE" to the SWIOTLB Kconfig entry too? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
