On Wed, May 08, 2013 at 09:24:44AM +0200, Arnd Bergmann wrote: > It probably should. The main thing is that the dma_mask setting in > of_platform (and elsewhere) is a mess and that nobody so far had the > guts to try to get it right for good. > > Setting a 32 bit DMA mask is /probably/ the right default on all > ARM systems, but there are caveats: > > - Once you get to systems with larger than 32 bit addressing (powerpc64, > arm64, arm32 with LPAE), it's not so obvious: you may have some devices > that need a 32 bit mask and some that need a 64 bit mask. This is precisely why drivers should be using dma_set_mask() and the coherent version to provide the mask for which the driver knows about - iow, if the device itself is only capable of 32-bit DMA, then the device must use dma_set_mask(dev, DMA_BIT_MASK(32)). -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
