On Tue, 30 May 2017, Brian Norris wrote:
> Sorry to respond to myself. Thomas, your reply to another mail in this
> series helped me to notice:
>
> On Tue, May 30, 2017 at 04:19:58PM -0700, Brian Norris wrote:
> > Side note: for issues like the first problem above, I wonder why there
> > isn't a flag that once could pass to request_irq() that suggests the IRQ
> > should be initially disabled?
>
> Is that what IRQ_NOAUTOEN is for?
Yes.
> > I know this wouldn't work for shared
> > interrupts (but request_irq() could reject that combination, no?)
>
> Hehe, but then I see this, for example, when grepping around:
>
> drivers/usb/dwc3/dwc3-omap.c:
>
> irq_set_status_flags(omap->irq, IRQ_NOAUTOEN);
> ret = devm_request_threaded_irq(dev, omap->irq, dwc3_omap_interrupt,
> dwc3_omap_interrupt_thread,
> IRQF_SHARED,
> "dwc3-omap", omap);
>
> IIUC, that's quite broken, no?
Indeed. Because the interrupt could have been requested by some other
driver already. In that case IRQ_NOAUTOEN has no effect at all.
We probably should check that in __setup_irq() and yell at people.
Thanks,
tglx
