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

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

On Tue, Jan 17, 2017 at 08:31:03AM -0800, Tony Lindgren wrote:
> * Bin Liu <b-liu-l0cyMroinI0@public.gmane.org> [170117 08:22]:
> > 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.
> 
> What kind of additional issues are you seeing not described in the $subject
> patch?

I didn't take a note and don't remember if those are in the $subject
patch. But

- enumeration begining with a reset that the device doesn't accept
  address X, error code -71; or

- console fooding with cppi error code -115 after thumb drive enumeration.

Again, I only tried for a few minutes and didn't take a note, since I
don't have time to look at this ATM.

Regards,
-Bin.
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