Message-ID: <1514944049.2523.28.camel@hadess.net>
Subject: Re: [RFC PATCH] input: Add disable sysfs entry for every input
 device
From: Bastien Nocera <hadess@hadess.net>
To: Pali =?ISO-8859-1?Q?Roh=E1r?= <pali.rohar@gmail.com>
Cc: Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>,
        Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        Sebastian Reichel <sre@kernel.org>,
        Pavel Machek <pavel@ucw.cz>,
        Mauro Carvalho Chehab <mchehab@osg.samsung.com>,
        Chuck Ebbert <cebbert.lkml@gmail.com>,
        Henrik Rydberg <rydberg@euromail.se>,
        linux-input@vger.kernel.org, linux-kernel@vger.kernel.org
Date: Wed, 03 Jan 2018 02:47:29 +0100
In-Reply-To: <20180102215437.i3x2j6jvxtac4ntt@pali>
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         <1483370825.2420.8.camel@hadess.net> <201701021809.58943@pali>
         <1483442481.2420.12.camel@hadess.net>
         <60c21c4d-bb81-342a-45e1-7e92313e05d7@gmail.com>
         <1483540655.2420.18.camel@hadess.net>
         <20180102215437.i3x2j6jvxtac4ntt@pali>
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On Tue, 2018-01-02 at 22:54 +0100, Pali Rohár wrote:
> On Wednesday 04 January 2017 15:37:35 Bastien Nocera wrote:
> > I don't doubt that the use cases should be catered for, I
> > essentially
> > did that same work without kernel changes for GNOME. What I doubt
> > is
> > the fuzzy semantics, the fact that the device is kept opened but no
> > data is sent (that's not power saving), that whether users are
> > revoked
> > or should be revoked isn't clear, and that the goal is basically to
> > work around stupid input handling when at the console. When running
> > a
> > display manager, this is all avoided.
> > 
> > If this were to go through, then the semantics and behaviour needs
> > to
> > be better explained, power saving actually made possible, and make
> > sure
> > that libinput can proxy that state to the users on the console. Or
> > an
> > ioctl added to the evdev device to disable them.
> 
> So, do you mean to implement this "disable" action as ioctl for
> particular /dev/input/event* device (instead of sysfs entry)?

Yes, so the device can be powered down without the device node being
closed and made unavailable. I don't know whether that's something
that's already possible for all cases, but there's already
opportunistic in a lot of drivers and subsystems.

This opens up a whole new wave of potential problems, but it's a more
generally useful mechanism, I would think.