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Date:   Fri, 5 Apr 2019 00:05:09 +0200
From:   Pavel Machek <pavel@ucw.cz>
To:     Dmitry Torokhov <dtor@google.com>
Cc:     Nick Crews <ncrews@chromium.org>,
        Guenter Roeck <groeck@google.com>,
        Enric Balletbo i Serra <enric.balletbo@collabora.com>,
        Benson Leung <bleung@chromium.org>, linux-leds@vger.kernel.org,
        Jacek Anaszewski <jacek.anaszewski@gmail.com>,
        Alexandre Belloni <alexandre.belloni@bootlin.com>,
        Alessandro Zummo <a.zummo@towertech.it>,
        linux-rtc@vger.kernel.org,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Duncan Laurie <dlaurie@chromium.org>,
        Simon Glass <sjg@google.com>
Subject: Re: [PATCH v5 3/3] platform/chrome: Standardize Chrome OS keyboard
 backlight name
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On Thu 2019-04-04 14:48:35, Dmitry Torokhov wrote:
> On Thu, Apr 4, 2019 at 1:42 PM Pavel Machek <pavel@ucw.cz> wrote:
> >
> > Hi!
> >
> > > > > And what to do if internal keyboard is not platform but USB? Like
> > > > > Google "Whiskers"? (I am not sure why you decided to drop my ment=
ion
> > > > > of internal USB keyboards completely off your reply).
> > > >
> > > > I don't have answers for everything. Even if you have USB keyboard,=
 you'll
> > > > likely still have backlight connected to embedded controller. If no=
t,
> > > > then maybe you have exception userland needs to know about.
> > > >
> > > > Still better than making everything an exception.
> > >
> > > You do not need to make everything exception. You just need to look
> > > beyond the name, and see how the device is connected. And then apply
> > > your exceptions for "weird" devices.
> >
> > "Where it is connected" is not interesting to the userland. "Is it
> > backlight for internal keyboard" is the right question. It may be
> > connected to embedded controller or some kind of controller over
> > i2c... my shell scripts should not need to know about architecture of
> > every notebook out there.
>=20
> Then your scripts will be failing for some setups.

Well, yes. Do you want to guess what "lp5523:kb3" is?

> > But I don't see why I should do additional work when its trivial for
> > kernel to just name the LED in an useful way.
> >
> > "platform::kbd_backlight" has no disadvantages compared to
> > "wilco::kbd_backlight" ... so lets just use it.
>=20
> It has disadvantages because it promises more than it can deliver IMO.
> If device name !=3D "platform::kbd_backlight" it does not mean that it
> is not internal keyboard.

My promise is if "platform::kbd_backlight" exists, it is backlight for
internal keyboard. (And second half is "if it is easy for kernel, we
name backlight for internal keyboard platform::kbd_backlight").

> And you still have not resolved how you will
> handle cases when there is more than one deice that can be considered
> internal and may have a backlight.

Is that realistic? How would that device look like?

									Pavel
--=20
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo=
g.html

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