Re: Get rid of IRQF_DISABLED - (was [PATCH] genirq: warn aboutIRQF_SHARED|IRQF_DISABLED)

[Russell King - ARM Linux]

On Mon, Nov 30, 2009 at 03:32:23PM +0000, Alan Cox wrote:
> On Mon, 30 Nov 2009 15:01:00 +0000
> Russell King - ARM Linux <linux@xxxxxxxxxxxxxxxx> wrote:
> > On Mon, Nov 30, 2009 at 02:47:02PM +0000, Alan Cox wrote:
> > > SHARED|DISABLED ought to WARN_ON() and if that doesn't motivate people
> > > then return -EINVAL.
> > 
> > That is an impossibility.  There is hardware out there (AT91) where
> > the timer interrupt is shared with other peripherals, and you end
> > up with a mixture of irqs-disabled and irqs-enabled handlers sharing
> > the same interrupt.
> 
> Well that will encourage people to fix it.
> 
> > My point is that if we outlaw irqs-disabled shared interrupts, it puts
> > Atmel AT91 support into immediate difficulties.
> 
> If a driver disables the timer irq across a tick aren't you already in
> trouble ?

Not with this clockevents code - you can miss timer interrupts and the core
time keeping code catches up automatically.
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