On Wednesday, 4 July 2007 21:49, Pavel Machek wrote:
> Hi!
>
> > Since we are now explicitly calling hibernation_ops->prepare() before
> > hibernation_ops->enter() in hibernation_platform_enter() (defined in
> > kernel/power/disk.c), ACPI should not call acpi_sleep_prepare(ACPI_STATE_S4)
> > from acpi_shutdown().
> >
> > Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
> > ---
> > drivers/acpi/sleep/poweroff.c | 3 ---
> > 1 file changed, 3 deletions(-)
> >
> > Index: linux-2.6.22-rc6/drivers/acpi/sleep/poweroff.c
> > ===================================================================
> > --- linux-2.6.22-rc6.orig/drivers/acpi/sleep/poweroff.c 2007-07-01 15:08:54.000000000 +0200
> > +++ linux-2.6.22-rc6/drivers/acpi/sleep/poweroff.c 2007-07-01 15:10:07.000000000 +0200
> > @@ -54,9 +54,6 @@ static int acpi_shutdown(struct sys_devi
> > case SYSTEM_POWER_OFF:
> > /* Prepare to power off the system */
> > return acpi_sleep_prepare(ACPI_STATE_S5);
> > - case SYSTEM_SUSPEND_DISK:
> > - /* Prepare to suspend the system to disk */
> > - return acpi_sleep_prepare(ACPI_STATE_S4);
> > default:
> > return 0;
>
> Hmm, I do not see why this is unneccessary... acpi wants to be
> notified of poweroff, and hooks in a pretty reasonable
> way. kernel/power does not seem to call acpi_sleep_prepare(). Hmm?
Please look at -mm.
We have
int hibernation_platform_enter(void)
{
int error;
if (hibernation_ops) {
kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK);
/*
* We have cancelled the power transition by running
* hibernation_ops->finish() before saving the image, so we
* should let the firmware know that we're going to enter the
* sleep state after all
*/
error = hibernation_ops->prepare();
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
if (!error)
error = hibernation_ops->enter();
} else {
error = -ENOSYS;
}
return error;
}
in there, which is exactly that.
The patch is necessary. :-) Otherwise ->prepare() will be called twice in a row.
Greetings,
Rafael
--
"Premature optimization is the root of all evil." - Donald Knuth
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