Messages in this thread | | | Date | Mon, 2 Mar 2009 15:01:33 -0800 | Subject | Re: [RFC][PATCH 1/4] PM: Rework handling of interrupts during suspend-resume (rev. 4) | From | Arve Hjønnevåg <> |
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On Sun, Mar 1, 2009 at 2:24 PM, Rafael J. Wysocki <rjw@sisk.pl> wrote: > From: Rafael J. Wysocki <rjw@sisk.pl> > > Introduce two helper functions allowing us to prevent device drivers > from getting any interrupts (without disabling interrupts on the CPU) > during suspend (or hibernation) and to make them start to receive > interrupts again during the subsequent resume, respectively. These > functions make it possible to keep timer interrupts enabled while the > "late" suspend and "early" resume callbacks provided by device > drivers are being executed. > > Use these functions to rework the handling of interrupts during > suspend (hibernation) and resume. Namely, interrupts will only be > disabled on the CPU right before suspending sysdevs, while device > drivers will be prevented from receiving interrupts, with the help of > the new helper function, before their "late" suspend callbacks run > (and analogously during resume). > > In addition, since the device interrups are now disabled before the > CPU has turned all interrupts off and the CPU will ACK the interrupts > setting the IRQ_PENDING bit for them, check in sysdev_suspend() if > any wake-up interrupts are pending and abort suspend if that's the > case. >
> +void resume_device_irqs(void) > +{ > + struct irq_desc *desc; > + int irq; > + > + for_each_irq_desc(irq, desc) > + if (desc->status & IRQ_SUSPENDED) > + enable_irq(irq); > +}
I think you need to clear IRQ_SUSPENDED here, not in enable_irq.
> @@ -222,8 +222,9 @@ static void __enable_irq(struct irq_desc > WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq); > break; > case 1: { > - unsigned int status = desc->status & ~IRQ_DISABLED; > + unsigned int status; > > + status = desc->status & ~(IRQ_DISABLED | IRQ_SUSPENDED); > /* Prevent probing on this irq: */ > desc->status = status | IRQ_NOPROBE; > check_irq_resend(desc, irq);
This only clears IRQ_SUSPENDED if the interrupt was not disabled elsewhere. If a driver calls interrupt_disable in suspend_late, but calls interrupt_enable lazily, resume_device_irqs will reenable the interrupt even though the driver has a disable reference.
The rest of the patch looks good.
-- Arve Hjønnevåg -- 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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