Re: [PATCH] PM: suspend_device_irqs(): don't disable wakeup IRQs

[Kim Kyuwon]

Rafael J. Wysocki wrote:
> On Saturday 23 May 2009, Kim Kyuwon wrote:
> > On Sat, May 23, 2009 at 7:29 AM, Rafael J. Wysocki <rjw@xxxxxxx> wrote:
> > > On Saturday 23 May 2009, Kim Kyuwon wrote:
> [--snip--]
> > > > You changed the really important part of Linux, which may affect most
> > > > processor architectures. I think you should be careful. If some of
> > > > architectures can't take care of it (they can implement
> > > > disable_irq_wake correctly in H/W level, will you revert your changes?
> > > No, the changes are not going to be reverted.  In fact things should have been
> > > done like this already much earlier.
> > >
> > > Now, do you have any particular example of a problem related to these changes
> > > or is it only a theoretical issue?
> > I'd CCing you when I'm sending a mail for this particular example of a example.
> > http://markmail.org/thread/fvt7d62arofon5xx
>
> Well, as I said above, reverting the changes that introduced
> [suspend|resume]_device_irqs() is not an option, becuase it was the only sane
> way to achieve the goal they were added for.  So, we need to fix the wake-up
> problem on your platform with the assumption that
> [suspend|resume]_device_irqs() are going to stay.
>
> For starters, would it be possible to teach the 'disable' hook of your
> platform's interrupt controller not to mask the IRQs that have both
> IRQ_WAKEUP and IRQ_SUSPENDED set?  That apparently would work around the
> wake-up interrupts problem.

Thank you for considering this issue and spending your time. In order to 
make your idea work, we need to add a dummy 'set_wake' hook which 
returns always zero. Anyway, IMO, I think your idea is good to work 
around this problem. But Kevin Hilman(OMAP PM Maintainer) would make 
final decision.

Buy the way, how can you handle the problem that a few interrupt are 
discarded in a small window? I can be sure they are discarded, because I 
have debugged defects which generate in sleep/resume state hundreds of 
times on ARM Processors(PXA310, S3C6410, OMAP3430). Wake-up interrupts 
are generated as soon as arch_suspend_enable_irqs() invoked.

Regards,
Kyuwon
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/