On Tue, Jun 21, 2011 at 12:06 AM, Russell King - ARM Linux
[off-list ref] 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.