linux-kernel - Re: [PATCH] gpiolib: Don't implicitly disable irq when masking

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Message-ID: <CACRpkda55gYEnwgLGX-73POCHsQv769ziS6L6oJzHY2coDD0pQ@mail.gmail.com>
Date:   Thu, 11 May 2023 22:48:52 +0200
From:   Linus Walleij <linus.walleij@...aro.org>
To:     Chris Packham <Chris.Packham@...iedtelesis.co.nz>
Cc:     "andy.shevchenko@...il.com" <andy.shevchenko@...il.com>,
        "brgl@...ev.pl" <brgl@...ev.pl>,
        Ben Brown <Ben.Brown@...iedtelesis.co.nz>,
        "linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Marc Zyngier <maz@...nel.org>,
        Hans Verkuil <hverkuil-cisco@...all.nl>
Subject: Re: [PATCH] gpiolib: Don't implicitly disable irq when masking

On Thu, May 11, 2023 at 10:36 PM Chris Packham
<Chris.Packham@...iedtelesis.co.nz> wrote:

> I spent yesterday trying to demonstrate the
> problem on a newer kernel. Some teething issues aside I can trigger the
> warning if I have a gpio-button using one of the pca9555 pins as an
> interrupt and then I export some of the other pins via sysfs.
>
> Interestingly the warning isn't triggered if I use a gpio-hog instead of
> exporting the pins.

What happens if you use the gpio character device instead of sysfs?

Like for example with the tools in tools/gpio or using libgpiod
example tools?

> I haven't figured out why that is but I'm assuming
> it's something to do with the hogged pins being excluded from the irq
> domain before it is registered.

If you write something to the "edge" file I can easily see things
going sidewise. The sysfs is really not a nice tool, which is why
it is deprecated.

Yours,
Linus Walleij