[PATCH 4/7] ALSA: pcm: use dma_can_mmap() to check if a device supports dma_mmap_*

[Christoph Hellwig]

On Mon, Aug 05, 2019 at 11:22:03AM +0200, Takashi Iwai wrote:
> This won't work as expected, unfortunately.  It's a bit tricky check,
> since the driver may have its own mmap implementation via
> substream->ops->mmap, and the dma_buffer.dev.dev might point to
> another object depending on the dma_buffer.dev.type.
> 
> So please replace with something like below:

>From my gut feeling I'd reorder it a bit to make it more clear like
this:

http://git.infradead.org/users/hch/misc.git/commitdiff/958fccf54d00c16740522f818d23f9350498e911

if this is fine it'll be in the next version, waiting for a little more
feedback on the other patches.