On Tue, Mar 22, 2016 at 10:53:21AM +0800, Shawn Lin wrote:
> >Strange, but on 4.4 there was some extra code in
> >dma_request_slave_channel() that wasn't in
> >dma_request_slave_channel_reason(). ...but looks like that all got
> >cleaned up in the same CL that added the new name.
>
> dma_request_chan already return ERR_PTR(-EPROBE_DEFER), but
> dma_request_slave_channel ignore this and rewrite it to be NULL.
> Strange behaviour looks to me. commit 0ad7c00057dc ("dma: add channel
> request API that supports deferred probe") did the right thing, but
> what happened then? It was drop for some reasons?
>
> Hello Vinod,
>
> Could you please elaborate some more infomation to commit 0ad7c00057dc
> ("dma: add channel request API that supports deferred probe") :) ?
The request API was cleaned up here and please see the Documentation on how
to do this.
See the commit a8135d0d7 - dmaengine: core: Introduce new, universal API to
request a channel
Thanks
--
~Vinod
