Re: [linux-pm] [PATCH] PM: runtime PM + idle: allow usage when interrupts are disabled

[Kevin Hilman <khilman@deeprootsystems.com>]

"Rafael J. Wysocki" <rjw@sisk.pl> writes:

> On Tuesday, August 10, 2010, Kevin Hilman wrote:
>> When using runtime PM in combination with CPUidle, the runtime PM
>> transtions of some devices may be triggered during the idle path.
>> Late in the idle sequence, interrupts will likely be disabled when
>> runtime PM for these devices is initiated.
>> 
>> Currently, the runtime PM core assumes methods are called with
>> interrupts enabled.  However, if it is called with interrupts
>> disabled, the internal locking unconditionally enables interrupts, for
>> example:
>> 
>> pm_runtime_put_sync()
>
> Please don't use that from interrupt context.  

I'm not using this in interrupt context.  I'm using it in process
context where interrupts are disabled, specifically, the idle thread.

> There's pm_runtime_put() exactly for this purpose that puts the
> _idle() call into a workqueue.

If I'm in my CPU's idle path, I don't want to activate a workqueue
because then I'll no longer be idle.

Kevin