On Tuesday 05 May 2015 11:24:03 Tom Lendacky wrote: > On 05/05/2015 11:13 AM, Suravee Suthikulanit wrote: > > On 5/5/2015 11:12 AM, Arnd Bergmann wrote: > >> On Tuesday 05 May 2015 11:09:38 Suravee Suthikulanit wrote: > >>> > >>> However, codes in several places are making use of dma_map_ops without > >>> checking if the ops are NULL (i.e. > >>> include/asm-generic/dma-mapping-common.h and in arch-specific > >>> implementation). If setting it to NULL is what we are planning to > >>> support, we would need to scrub the current code to put NULL check. > >>> Also, would you consider if that is safe to do going forward? > >>> > >>> > >> > >> I mean the dma_mask pointer, not dma_map_ops. > > Except a lot of drivers will actually set the dma_mask pointer during > probe (usually by setting dev->dma_mask = &dev->coherent_dma_mask or by > calling dma_coerce_mask_and_coherent). So I think the dummy_dma_ops > might be the safest way to go. Those drivers are broken already, I don't think we should worry about them. Let's just fix them properly when we run into problems with them. Basically any use of dma_coerce_mask_and_coherent() is an annotation for a bug where a driver used to set dev->dma_mask = &dev->coherent_dma_mask manually. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
