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From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Sat, 13 Jun 2020 14:54:51 +0300
Message-ID: <CAHp75Vckh3NERodBs3e8wo3NxbrP=BPRY5g7MLmA4szqLFcfjA@mail.gmail.com>
Subject: Re: [PATCH] lib: update DEBUG_SHIRQ docs to match reality
To:     Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc:     Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
        Krzysztof Kozlowski <krzk@kernel.org>,
        Oleksij Rempel <o.rempel@pengutronix.de>,
        Marc Kleine-Budde <mkl@pengutronix.de>,
        Thomas Gleixner <tglx@linutronix.de>
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On Sat, Jun 13, 2020 at 2:39 PM Wolfram Sang
<wsa+renesas@sang-engineering.com> wrote:
>
>
> > > There is no extra interrupt when registering a shared interrupt handler
> > > since 2011. Update the Kconfig text to make it clear and to avoid wrong
> > > assumptions when debugging issues found by it.
> > >
> >
> > I'm not sure.
> > I have recently fixed a bug in the IIO sensor during ->probe() due to
> > an issued test interrupt exactly as soon as the handler is registered.
>
> $ git grep DEBUG_SHIRQ_FIXME
> kernel/irq/manage.c:#ifdef CONFIG_DEBUG_SHIRQ_FIXME
>
> There is no place to enable this code.
>
> Maybe your case was like Krzysztof's case where the issue turned out to
> be the extra interrupt on deregistering after a deferred probe? He
> thought it was the initial interrupt but it wasn't.

Commit
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/iio/pressure/bmp280-core.c?id=97b31a6f5fb95b1ec6575b78a7240baddba34384

The relevant IRQ core code
https://elixir.bootlin.com/linux/latest/source/kernel/irq/manage.c#L1774

It runs it at deregistering, right.

-- 
With Best Regards,
Andy Shevchenko