Messages in this thread | | | Date | Sat, 7 Mar 2009 11:51:19 -0500 (EST) | From | Alan Stern <> | Subject | Re: [linux-pm] [RFC][PATCH][1/8] PM: Rework handling of interrupts during suspend-resume (rev. 5) |
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On Sat, 7 Mar 2009, Rafael J. Wysocki 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.
One thing about this isn't clear: the distinction between "wake-up" interrupts and other interrupts.
In an ideal world, the only pending interrupts during sysdev_suspend would be wake-up interrupts, because drivers would have prevented their devices from generating any other kind of IRQ and would have done all the necessary synchronization as part of their suspend (_not_ suspend_late) methods. Thus there would be no need to distinguish between wake-up and non-wake-up interrupts.
So perhaps you're worried about drivers that aren't sufficiently clever. Or is something deeper going on?
Alan Stern
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