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From:   Bartosz Golaszewski <brgl@bgdev.pl>
Date:   Thu, 25 May 2023 16:35:23 +0200
Message-ID: <CAMRc=Md2iFVMw14d4v-AjmcBniWF6r65VhcE5+HFsvH=VTdSxA@mail.gmail.com>
Subject: Re: using libgpiod to replace sysfs ABI (was Re: [PATCH] gpiolib:
 Avoid side effects in gpio_is_visible())
To:     Andy Shevchenko <andy.shevchenko@gmail.com>
Cc:     Chris Packham <Chris.Packham@alliedtelesis.co.nz>,
        Kent Gibson <warthog618@gmail.com>,
        "linux-gpio@vger.kernel.org" <linux-gpio@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
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On Thu, May 25, 2023 at 11:13=E2=80=AFAM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
>
> On Thu, May 25, 2023 at 2:53=E2=80=AFAM Chris Packham
> <Chris.Packham@alliedtelesis.co.nz> wrote:
> > On 24/05/23 17:41, Kent Gibson wrote:
>
> ...
>
> > It'd also be great if there was some way of ensuring that a line's stat=
e
> > is kept after the application has released the request (i.e. the txdis
> > case I mentioned). But that probably needs work on the kernel side to
> > make such guarantees.
>
> Won't happen. It will require too much of strictness to be added into
> the kernel with likely breakage of the existing code and
> documentation. What is being discussed is a D-Bus (like?) daemon +
> Policy in user space that will allow user / process / cgroup / etc to
> "own" the line and track its state.
>

It's already WiP[1]. I'm trying to keep the footprint minimal with
only GLib and dbus required at run-time.

Bart

[1] https://github.com/brgl/libgpiod-private/tree/topic/dbus