Messages in this thread | | | From | "Rafael J. Wysocki" <> | Subject | Re: [PATCH] swsusp: Disable nonboot CPUs before entering platform suspend | Date | Fri, 9 Mar 2007 08:58:55 +0100 |
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On Wednesday, 7 March 2007 22:07, Pavel Machek wrote: > Hi! > > > Prevent the WARN_ON() in arch/x86_64/kernel/acpi/sleep.c:init_low_mapping() > > from triggering by disabling nonboot CPUs before we finally enter the platform > > suspend. > > > > Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> > > --- > > kernel/power/disk.c | 1 + > > kernel/power/user.c | 2 +- > > 2 files changed, 2 insertions(+), 1 deletion(-) > > > > Index: linux-2.6.21-rc2-mm2/kernel/power/disk.c > > =================================================================== > > --- linux-2.6.21-rc2-mm2.orig/kernel/power/disk.c > > +++ linux-2.6.21-rc2-mm2/kernel/power/disk.c > > @@ -61,6 +61,7 @@ static void power_down(suspend_disk_meth > > switch(mode) { > > case PM_DISK_PLATFORM: > > if (pm_ops && pm_ops->enter) { > > + disable_nonboot_cpus(); > > kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK); > > pm_ops->enter(PM_SUSPEND_DISK); > > break; > > ...so, if pm_ops is non-null, power_down does nonboot cpu disabling, > otherwise we proceed with cpus enabled? > > That looks ugly. > > Is the warning bogus?
Well, maybe. I'm not sure.
> Or maybe we should *always* disable nonboot cpus in powerdown path?
I think we should do that.
> > Index: linux-2.6.21-rc2-mm2/kernel/power/user.c > > =================================================================== > > --- linux-2.6.21-rc2-mm2.orig/kernel/power/user.c > > +++ linux-2.6.21-rc2-mm2/kernel/power/user.c > > @@ -398,9 +398,9 @@ static int snapshot_ioctl(struct inode * > > > > case PMOPS_ENTER: > > if (data->platform_suspend) { > > + disable_nonboot_cpus(); > > kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK); > > error = pm_ops->enter(PM_SUSPEND_DISK); > > - error = 0; > > } > > break; > > Foe an userland application, disabling cpus during pmops_enter is at > least surprising.......
Yes, but this is not a usual ioctl(). OTOH, we can call enable_nonboot_cpus() if pm_ops->enter(PM_SUSPEND_DISK) returns an error (otherwise it souldn't return at all, no?).
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