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

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Message-ID: <a3a6c80a-724c-e2fb-9597-b14a302c5ff4@siemens.com>
Date:   Wed, 17 Mar 2021 07:57:44 +0100
From:   Jan Kiszka <jan.kiszka@...mens.com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Andy Shevchenko <andy@...nel.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>
Subject: Re: [PATCH v4 2/2] gpio: sch: Hook into ACPI SCI handler to catch
 GPIO edge events

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@...mens.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.

Jan

> 
> 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.
> 

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