Re: [PATCH 0/11] ACPI: Fixes and cleanups related to iomaps management

Rafael J. Wysocki
2011-01-23T20:35:52Z

On Sunday, January 23, 2011, Henrique de Moraes Holschuh wrote:
> On Sat, 22 Jan 2011, Rafael J. Wysocki wrote:
> > > I discovered CONFIG_THINKPAD_ACPI caused suspend-to-disk to hang. I
> > > need the Thinkpad ACPI to control the fan and bluetooth. It looks like
> > > the thinkpad acpi is trying acquire locks while suspending. Disabling
> > > cmos, light, led and hotkeys makes suspend-to-disk works again.
> >
> > Well, we should tell the thinkpad_acpi maintainer about that, then (CCed).
>
> What are the requirements re. mutexes for sleep-to-disk versus sleep-to-ram?

No difference. Basically, there are two differences between suspend and
hibernation, as far as drivers are concerned:
(1) It's better to use the ->freeze()/->thaw() and ->poweroff()/->restore()
callbacks for hibernation.
(2) It may be _much_ more difficult to get free memory during hibernation
(so theoretically attempts to get memory during hibernation are more likely
to block).

> Did something change in that area that caused the driver to hang? A pointer
> to the ML threads, documentation, or patchset/git commit with those changes
> would be enough answer, and I will pursue it from there.

I'm not aware of any such changes.

Besides, the problem reported by Jeff seems to be caused by CPU hotplug.

Thanks,
Rafael