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From:   Mat King <mathewk@google.com>
Date:   Wed, 2 Oct 2019 11:13:50 -0600
Message-ID: <CAL_quvTNvnusdercRJhdXYDzBB=qy3cTrsPAuJSpE_tpWhnCmQ@mail.gmail.com>
Subject: Re: New sysfs interface for privacy screens
To:     Jonathan Corbet <corbet@lwn.net>
Cc:     linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
        Greg KH <gregkh@linuxfoundation.org>, rafael@kernel.org,
        Ross Zwisler <zwisler@google.com>,
        Rajat Jain <rajatja@google.com>,
        Lee Jones <lee.jones@linaro.org>,
        Daniel Thompson <daniel.thompson@linaro.org>,
        Jingoo Han <jingoohan1@gmail.com>,
        Alexander Schremmer <alex@alexanderweb.de>
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On Wed, Oct 2, 2019 at 9:46 AM Jonathan Corbet <corbet@lwn.net> wrote:
>
> On Tue, 1 Oct 2019 10:09:46 -0600
> Mat King <mathewk@google.com> wrote:
>
> > I have been looking into adding Linux support for electronic privacy
> > screens which is a feature on some new laptops which is built into the
> > display and allows users to turn it on instead of needing to use a
> > physical privacy filter. In discussions with my colleagues the idea of
> > using either /sys/class/backlight or /sys/class/leds but this new
> > feature does not seem to quite fit into either of those classes.
>
> FWIW, it seems that you're not alone in this; 5.4 got some support for
> such screens if I understand things correctly:
>
>   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=110ea1d833ad
>
> jon

Thanks Jon, I had seen that as well and I should have mentioned it in
my original post. That patch exposes the privacy screen using
/proc/acpi which does not seem ideal when adding more privacy screen
support into the kernel.