[221/272] PM / Runtime: Dont enable interrupts while running in_interrupt

Greg KH
2011-02-16T00:24:37Z

From: Alan Stern <stern@rowland.harvard.edu>

commit c3810c88788d505d4ffd786addd111b745e42161 upstream.

This patch (as1445) fixes a bug in the runtime PM core left over from
the addition of the no_callbacks flag. If this flag is set then it is
possible for rpm_suspend() to be called in_interrupt, so when
releasing spinlocks it's important not to re-enable interrupts.

To avoid an unnecessary save-and-restore of the interrupt flag, the
patch also inlines a pm_request_idle() call.

This fixes Bugzilla #27482.

(The offending code was added in 2.6.37, so it's not necessary to apply
this to any earlier stable kernels.)

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: tim blechmann <tim@klingt.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/base/power/runtime.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -404,12 +404,15 @@ static int rpm_suspend(struct device *de
goto out;
}

+ /* Maybe the parent is now able to suspend. */
if (parent && !parent->power.ignore_children) {
- spin_unlock_irq(&dev->power.lock);
+ spin_unlock(&dev->power.lock);

- pm_request_idle(parent);
+ spin_lock(&parent->power.lock);
+ rpm_idle(parent, RPM_ASYNC);
+ spin_unlock(&parent->power.lock);

- spin_lock_irq(&dev->power.lock);
+ spin_lock(&dev->power.lock);
}