[PATCH 11/31] dma: add channel request API that supports deferred probe

[Dan Williams]

On Fri, Nov 22, 2013 at 4:17 PM, Stephen Warren <swarren at wwwdotorg.org> wrote:
> No, it's a bug because if dma_request_slave_channel() is documented to
> return valid-or-ERR, then assuming that it can never return NULL is
> inconsistent with that. The translation is only possible if it's
> documented to return valid-or-ERR-but-never-NULL.

Yes!  We are in violent agreement about this point.  Make
dma_request_slave_channel return valid-or-ERR-but-never-NULL, and show
me the compat user that would care if it got an EPROBE_DEFER instead
of ENODEV.