Messages in this thread |  | | | From | Kim Kyuwon <> | | Date | Sat, 30 May 2009 16:40:31 +0900 | | Subject | Re: [PATCH] PM: suspend_device_irqs(): don't disable wakeup IRQs |
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On Sat, May 30, 2009 at 4:34 PM, Kim Kyuwon <chammoru@gmail.com> wrote: > On Sat, May 30, 2009 at 8:35 AM, Rafael J. Wysocki <rjw@sisk.pl> wrote: >> On Monday 25 May 2009, Kim Kyuwon wrote: >>> 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@sisk.pl> 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. >> >> Sorry for the delayed response. >> >> If the wake-up interrupts are not masked, they will be delivered to the drivers >> as soon as arch_suspend_enable_irqs() has run. So, if the drivers are able to >> handle them at this point (ie. before resume_device_irqs() is called), they >> won't be lost. > > Thank you for your response! > > Your suspend_device_irqs() disables all IRQs(except timer IRQ) while > entering suspend. i.e. Before invoking resume_device_irqs() or > resume_noirq callback, all IRQs(except timer IRQ) is in IRQ_DISABLED > status. Right? > But if an IRQ is in IRQ_DISABLED status, its interrupt handler can be
Sorry: *Can't be*
> invoked. (As you know, all IRQs with IRQ_DISABLE are not handled in > handle_level_irq function). Thus, even if the wake-up interrupts are > not masked, the drivers are not able to handle interrupts, because the > interrupt handler can't be invoked due to IRQ_DISABLED set by > suspend_device_irqs(). > >> The only problem I see is that the drivers may expect their >> ->resume_noirq() callbacks to be executed first. > > resume_noirq() callbacks are also invoked after arch_suspend_enable_irqs(). > > Regards, > Kyuwon >
-- Kyuwon (규원) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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