Re: [PATCH v4 2/2] gpio: sch: Hook into ACPI SCI handler to catch GPIO edge events

Andy Shevchenko
2021-03-17T09:53:17Z

On Wed, Mar 17, 2021 at 07:57:44AM +0100, Jan Kiszka wrote:
> On 16.03.21 21:49, Andy Shevchenko wrote:
> > On Tue, Mar 16, 2021 at 06:26:13PM +0200, Andy Shevchenko wrote:
> >> From: Jan Kiszka <jan.kiszka@siemens.com>
> >>
> >> Neither the ACPI description on the Quark platform provides the required
> >> information is to do establish generic handling nor hardware capable of
> >> doing it. According to the datasheet the hardware can generate SCI events.
> >> Therefore, we need to hook from the driver directly into SCI handler of
> >> the ACPI subsystem in order to catch and report GPIO-related events.
> >>
> >> Validated on the Quark-based IOT2000 platform.
> >
> > This patch must be dropped completely. SCI handler is not correct way to do
> > this. The proper way (and we have already few examples in the kernel) is to
> > register GPE event.
>
> As explained above, this is not supported by the preexisting firmware,
> and there won't be any updates to it anymore.
>
> This platform is history, the SoC was discontinued by Intel long ago,
> and our devices reaching their support end as well. The race to upstream
> was lost in this case - backlog too long, we being too slow.

So you have no device to test and there is actually no device which has this
capability in the wild.

Am I reading this correct?

In any case, we have platforms in the wild that actually support GPEs and this
makes sense for them.

> > It took me a while to gather all bits of this puzzle.
> >
> > At least now I get an event, but kernel oopses, I'll continue debugging
> > tomorrow.

--
With Best Regards,
Andy Shevchenko