On Tuesday, January 25, 2011, Alan Stern wrote:
> 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@xxxxxxxxxxxxxxxxxxx>
> Reported-by: tim blechmann <tim@xxxxxxxxxx>
> CC: <stable@xxxxxxxxxx>
Applied to suspend-2.6/pm-fixes, thanks Alan!
> ---
>
> Index: usb-2.6/drivers/base/power/runtime.c
> ===================================================================
> --- usb-2.6.orig/drivers/base/power/runtime.c
> +++ usb-2.6/drivers/base/power/runtime.c
> @@ -407,12 +407,15 @@ static int rpm_suspend(struct device *de
> goto out;
> }
>
> + /* Maybe the parent is now able to suspend. */
> if (parent && !parent->power.ignore_children && !dev->power.irq_safe) {
> - 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);
> }
>
> out:
>
>
>
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