Re: [PATCH 1/10] PM: Rework handling of interrupts during suspend-resume (rev. 5)

Rafael J. Wysocki
2009-03-11T22:03:40Z

On Wednesday 11 March 2009, Thomas Gleixner wrote:
> On Wed, 11 Mar 2009, Rafael J. Wysocki wrote:
> > On Wednesday 11 March 2009, Thomas Gleixner wrote:
> > > > +EXPORT_SYMBOL_GPL(suspend_device_irqs);
> > >
> > > I'm not too enthusiastic about this open coded implementation of
> > > disable_irq() with slightly different semantics.
> >
> > The difference in semantics is important IMO, otherwise I woulndn't have
> > done that. In particular, IMO, the condition should be under the spinlock IMO
> > and I'd rather not synchronize all interrupts we don't really disable here.
>
> I don't say that the difference is not relevant. But the code is
> almost the same and disable_irq() could have the sync_irq optimization
> as well.

Agreed.

> > > Can we please move the fiddling with desc->* into
> > > kernel/irq/manage.c and share the code there ?
> >
> > Can you please discuss that with Ingo? I moved that from manage.c at his
> > request.
>
> Hmrpf. Will do. I just want to avoid that we have scattered functions
> which deal with the guts of the irq code all over the place.

I understand your concern, I'd prefer to avoid that too.

> I'm fine with your loop in irq/pm.c, but the actual handling of the irq
> internals should remain in manage.c.

Well, perhaps we can add a parameter to disable_irq_nosync() telling it not
to disable the interrupt if it's a timer one? Something like

void disable_irq_nosync(unsigned int irq, bool skip_timer) etc.?

Also, it could return a value meaning whether or not the interrupt has been
actually disabled.

> I'll have a closer look how to solve this.

Thanks!

Best,
Rafael