Re: [RFC][PATCH 1/3] Hibernation: Enter platform hibernation state in a consisten way (rev. 2)

Pavel Machek
2007-08-27T12:25:01Z

Hi!

> > > Make hibernation_platform_enter() execute the enter-a-sleep-state sequence
> > > instead of the mixed shutdown-with-entering-S4 thing.
> > >
> > > Replace the shutting down of devices done by kernel_shutdown_prepare(), before
> > > entering the ACPI S4 sleep state, with suspending them and the shutting down of
> > > sysdevs with calling device_power_down(PMSG_SUSPEND) (just like before entering
> > > S1 or S3, but the target state is now S4). Also, disable the nonboot CPUs
> > > before entering the sleep state (S4), which generally always is a good idea.
> > >
> > > This is known to fix the "double disk spin down during hibernation" on some
> > > machines, eg. HPC nx6325 (ref. http://lkml.org/lkml/2007/8/7/316 and the
> > > following thread). It also generally causes the hibernation state (ACPI S4) to
> > > be entered faster.
> > >
> > > Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
> > > ---
> > > kernel/power/disk.c | 55 ++++++++++++++++++++++++++++++++++++++--------------
> > > 1 file changed, 41 insertions(+), 14 deletions(-)
> > >
> >
> > > + local_irq_disable();
> > > + error = device_power_down(PMSG_SUSPEND);
> > > + if (!error) {
> > > + error = hibernation_ops->enter();
> > > + /* We should never get here */
> >
> > Are you sure it is good idea to enable interrupts/power up devices
> > when this happens?
>
> Hm. No, I'm not.
>
> > AFAICT image is already on disk an intact at this point, safe thing to do is
> > while(1);...
>
> OK
>
> Like this?

Yes, like this. ACK.
Pavel

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