[...]
> > The "suspend" part is kind of a distraction to me here, because that really
> > only is about sharing an IRQ with a timer and the "your interrupt handler
> > may be called when the device is suspended" part is just a consequence of that.
> >
> > So IMO it's better to have "TIMER" in the names to avoid encouraging people to
> > abuse this for other purposes not related to timers.
>
> Sorry to be late to the bike-shed party, but what about:
[...]
> arch/arm/mach-omap2/mux.c: omap_hwmod_mux_handle_irq, IRQF_SHARED | IRQF_NO_SUSPEND,
> arch/arm/mach-omap2/pm34xx.c: _prcm_int_handle_io, IRQF_SHARED | IRQF_NO_SUSPEND, "pm_io",
> drivers/pinctrl/pinctrl-single.c: IRQF_SHARED | IRQF_NO_SUSPEND,
These are chained IRQ handlers. If any of these have a chained timer irq
then the IRQF_NO_SUSPEND may be legitimate. I can't imagine why these
would be shared, however.
It also looks like these abuse IRQF_NO_SUSPEND for wakeup interrupts.
> drivers/rtc/rtc-pl031.c: .irqflags = IRQF_SHARED | IRQF_NO_SUSPEND,
This looks to be an abuse and should use {enable,disable}_irq_wake.
However, we'd then need to handle mismatch with wakeup interrupts (which
is effectively the same problem as sharing with a timer).
> drivers/mfd/ab8500-debugfs.c: IRQF_SHARED | IRQF_NO_SUSPEND,
> drivers/mfd/ab8500-gpadc.c: IRQF_NO_SUSPEND | IRQF_SHARED, "ab8500-gpadc-sw",
> drivers/mfd/ab8500-gpadc.c: IRQF_NO_SUSPEND | IRQF_SHARED, "ab8500-gpadc-hw",
> drivers/power/ab8500_btemp.c: IRQF_SHARED | IRQF_NO_SUSPEND,
> drivers/power/ab8500_charger.c: IRQF_SHARED | IRQF_NO_SUSPEND,
> drivers/power/ab8500_fg.c: IRQF_SHARED | IRQF_NO_SUSPEND,
> drivers/usb/phy/phy-ab8500-usb.c: IRQF_NO_SUSPEND | IRQF_SHARED,
> drivers/usb/phy/phy-ab8500-usb.c: IRQF_NO_SUSPEND | IRQF_SHARED,
> drivers/usb/phy/phy-ab8500-usb.c: IRQF_NO_SUSPEND | IRQF_SHARED,
All the *ab8500* look cargo-culted. There's other nonsense in these
(e.g. mutex_lock in irq handlers...). I suspect these are not
legitimate.
> drivers/watchdog/intel-mid_wdt.c: IRQF_SHARED | IRQF_NO_SUSPEND, "watchdog",
Watchdogs could be a legitimate case, but this driver relies on another
timer and the timeout irq handler simply calls panic(), which seems a
little extreme.
> Is there a single legitimate user in that list? If so, the TIMER name
> might be misleading.
The watchdog case could be legitimate, and with drivers corrected to use
{enable,disable}_irq_wake we'll need to handle mismatch for wakeup
interrupts too.
Having separate flags for sharing with timers and sharing with wakeup
sources seems redundant, and IRQF_SHARED_TIMER_OK would be misleading.
Thanks,
Mark.
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