Re: [linux-next][PATCH] usb: dwc3: omap: remove IRQ_NOAUTOEN used with shared irq

[Grygorii Strashko]

On 07/02/2017 11:27 PM, Vignesh R wrote:
> Hi,
>
> On Saturday 01 July 2017 01:04 AM, Strashko, Grygorii wrote:
> > On 06/29/2017 01:03 AM, Tony Lindgren wrote:
> > > * Vignesh R <vigneshr@xxxxxx> [170628 21:21]:
> > > > On Thursday 29 June 2017 05:01 AM, Strashko, Grygorii wrote:
> > > > > IRQ_NOAUTOEN can't be used with shared IRQs and Kernel now will triggers
> > > > > warning if it happns, since commit 04c848d39879 ("genirq: Warn when
> > > > > IRQ_NOAUTOEN is used with shared interrupts"). And this is the case for
> > > > > OMAP DWC 3 driver.
> > > > >
> > > > > Hence, remove IRQ_NOAUTOEN flag and instead call disable_irq() before
> > > > > disabling PM runtime in probe error path handling.
> > > >
> > > > Or, how about requesting the irq at the end of probe after extcon
> > > > registration?
> > >
> > > Hmm yeah, what prevents the issue that we tried to fix with commit
> > > 12a7f17fac5b ("usb: dwc3: omap: fix race of pm runtime with irq handler
> > > in probe")?
> >
> > No, I think. There should be the disable_irq() call any way
> > before pm_runtime_put_sync(dev);| pm_runtime_disable(dev); -
> > once IRQ is requested driver can't know if IRQ handler is running now or not
> > unless it will call disable_irq()/free_irq().
> >
> > But, I've also thought about moving request_irq() down (seems
> > it can be moved even after of_platform_populate()).
> > looks like it can be separate patch.
>
> commit 12a7f17fac5b says PM runtime can race with IRQ handler when
> deferred probing happening due to extcon, therefore IRQ_NOAUTOEN was set
> and disable_irq() call was added. If IRQ handler registration is moved
> to a place after of_platform_populate(), then we can be sure that extcon
> is registered and there wont be any deferred probe or race with irq
> handler and PM runtime. Would disable_irq() still be needed then?

You might be correct, so feel free to send a patch.

--
regards,
-grygorii