Re: [PATCHv2] dmaengine: cppi41: Fix oops in cppi41_runtime_resume

[Bin Liu <b-liu-l0cyMroinI0@public.gmane.org>]

On Tue, Jan 17, 2017 at 08:11:39AM -0800, Tony Lindgren wrote:
> * Bin Liu <b-liu-l0cyMroinI0@public.gmane.org> [170117 05:00]:
> > On Mon, Jan 16, 2017 at 03:54:29PM -0800, Tony Lindgren wrote:
> > > Anyways, for the -rc series oops, we can just leave out the WARN_ON
> > > parts for now until drivers/usb/musb/musb_cppi41.c is fixed too.
> > 
> > Giving that cppi is a submodule inside the usb subsysytem and it does't
> > have separate power rail or clock, what is the benefit to adding runtime
> > PM in the cppi driver?
> 
> Good question. We need at least minimal support to enable things for
> probe and then idle cppi41 properly if only cppi41.ko is loaded with no
> USB modules.
> 
> But yeah now that musb does runtime PM based on the cable detection, we
> pretty much guarantee that cppi41 is always enabled when USB is in use.
> 
> And if there are no other devices using cppi41 dma on davinci, we can
> simplify the PM runtime a bit for cppi41.

This might be a good idea. I didn't have much time to play with this
cppi41 runtime PM, but it seems I am having more issues than you and
others seeing.

Regards,
-Bin.
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