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

[Dan Williams]

On Mon, Nov 25, 2013 at 11:00 AM, Stephen Warren <swarren at wwwdotorg.org> wrote:
> I suppose an alternative would be to remove that flag, and have the loop
> in of_dma_request_slave_channel() initially ignore any unregistered DMA
> controllers, and still continue to look through the property for any
> alternative controller, and return a channel from one if it is found.
> Then, at the very end of the function, we could always return
> -EPROBE_DEFER if any unregistered DMA controllers were found, otherwise
> return -ENODEV. That would keep compatible behaviour, but it would mean
> that device probe order would/could influence which dmas entry provided
> the channel, since some entries might be ignored based simply on
> timing/ordering of DMA controller registration. Is that acceptable?
>

Yes, I think this option makes the most sense, and is just as
susceptible to probe order as the current implementation.