Hi Jon,
On Tue, Feb 16, 2016 at 10:28 AM, Jon Hunter <jonathanh@xxxxxxxxxx> wrote:
> On 09/02/16 15:19, Geert Uytterhoeven wrote:
>> The R-Car GPIO driver handles Runtime PM for requested GPIOs only.
>>
>> When using a GPIO purely as an interrupt source, no Runtime PM handling
>> is done, and the GPIO module's clock may not be enabled.
>>
>> To fix this:
>> - Add .irq_request_resources() and .irq_release_resources() callbacks
>> to handle Runtime PM when an interrupt is requested,
>
> I know that when I was looking at runtime-pm support for IRQ chips
> (which I have been meaning to get back too), the problem with
> irq_request_resources() is that it is called from the context of a
> spinlock (in __setup_irq()). You mentioned that you have not seen any
> reports of might_sleep_if(), but have you ensured that it is actually
> runtime resuming in your testing and you are not getting lucky?
It must be runtime-resuming, because without the call to pm_runtime_get_sync()
interrupts don't work.
> An alternative for you might be to use the
> irq_bus_lock/irq_bus_sync_unlock callbacks. See what Grygorii
> implemented for OMAP in commit aca82d1cbb49 ("gpio: omap: move pm
> runtime in irq_chip.irq_bus_lock/sync_unlock").
Thanks, that indeed looks interesting...
> As I mentioned I do plan to get back to the series for adding runtime-pm
> support for IRQ chips, in the next week or two.
Looking forward to it!
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
