On Sat, May 30, 2009 at 8:35 AM, Rafael J. Wysocki <rjw@xxxxxxx> 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@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. > > 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 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 _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
