Re: [RFC][PATCH 2/2] PM: Rework handling of interrupts during suspend-resume

Rafael J. Wysocki
2009-02-23T14:48:11Z

On Monday 23 February 2009, Ingo Molnar wrote:
>
> * Rafael J. Wysocki <rjw@sisk.pl> wrote:
>
> > > > Index: linux-2.6/arch/x86/kernel/apm_32.c
> > > > ===================================================================
> > > > --- linux-2.6.orig/arch/x86/kernel/apm_32.c
> > > > +++ linux-2.6/arch/x86/kernel/apm_32.c
> > >
> > > > +
> > > > + suspend_device_irqs();
> > > > device_power_down(PMSG_SUSPEND);
> > > > +
> > > > + local_irq_disable();
> > >
> > > hm, this is a very repetitive pattern, all around the various
> > > suspend/resume variants. Might make sense to make:
> > >
> > > device_power_down(PMSG_SUSPEND);
> > >
> > > do the irq line disabling plus the local irq disabling
> > > automatically. That also means it cannot be forgotten. The
> > > symmetric action should happen for PMSG_RESUME.
> > >
> > > Is there ever a case where we want a different pattern?
> >
> > Even if there's no such case, I prefer to call
> > local_irq_disable() explicitly in here, so that it's clearly
> > known where it happens to anyone reading this code.
>
> That property can be implied in the function name:
>
> device_power_down_irq_disable(PMSG_SUSPEND);
>
> Open-coding it, if it looks the same in all the cases just
> increases the chances that someone somewhere copies them
> incorrectly.

Well, I see your point, but in that case I'd rather couple the disabling of
local interrupts on the CPU with sysdev_suspend and the disabling (or whatever
Eric would like to call that) of device interrupts with device_power_down().

Thanks,
Rafael