Re: [PATCH] PCI PM: Restore standard config registers of all devices early (was: Re: EeePC resume failure - timers)

Jesse Barnes
2009-01-16T20:59:56Z

On Friday, January 16, 2009 12:54 pm Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rjw@sisk.pl>
> Subject: PCI PM: Restore standard config registers of all devices early
>
> There is a problem in our handling of suspend-resume of PCI devices
> that many of them have their standard config registers restored with
> interrupts enabled and they are put into the full power state with
> interrupts enabled as well. This may lead to the following scenario:
> * an interrupt vector is shared between two or more devices
> * one device is resumed earlier and generates an interrupt
> * the interrupt handler of another device tries to handle it and
> attempts to access the device the config space of which hasn't
> been restored yet and/or which still is in a low power state
> * the system crashes as a result
>
> To prevent this from happening we should restore the standard
> configuration registers of all devices with interrupts disabled and
> we should put them into the D0 power state right after that.
> Unfortunately, this cannot be done using the existing
> pci_set_power_state(), because it can sleep. Also, to do it we have
> to make sure that the config spaces of all devices were actually
> saved during suspend.
>
> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

Thanks Rafael, I stuffed this one into my for-linus branch. I'd like it to go
through a linux-next cycle before pushing it to Linus, but if he's impatient
to get it into -rc2 he can always pull sooner (there's only one other small
fix in there atm).

--
Jesse Barnes, Intel Open Source Technology Center