Re: [Linaro-mm-sig] [PATCH 7/8] common: dma-mapping: change alloc/free_coherent method to more generic alloc/free_attrs

On Tue, Jun 21, 2011 at 12:06 AM, Russell King - ARM Linux linux@arm.linux.org.uk wrote:

Wrong - there is a difference.  For pre-ARMv6 CPUs, it returns memory with different attributes from DMA coherent memory.

And we're not going to sweep away pre-ARMv6 CPUs any time soon.  So you can't ignore dma_alloc_writecombine() which must remain to sanely support framebuffers.

OK. Thanks.

Then, I think we can implement dma_alloc_writecombine() away from dma_map_ops. IMHO, those devices that use dma_alloc_writecombine() are enough with the default dma_map_ops. Removing a member from dma_map_ops is too heavy work.