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Date: Fri, 19 Jan 2024 23:14:08 +0100
From: Pavel Machek <pavel@ucw.cz>
To: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>,
	Hans de Goede <hdegoede@redhat.com>,
	Werner Sembach <wse@tuxedocomputers.com>, jikos@kernel.org,
	Jelle van der Waa <jelle@vdwaa.nl>,
	Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>,
	Lee Jones <lee@kernel.org>, linux-kernel@vger.kernel.org,
	"dri-devel@lists.freedesktop.org" <dri-devel@lists.freedesktop.org>,
	linux-input@vger.kernel.org, ojeda@kernel.org,
	linux-leds@vger.kernel.org,
	Benjamin Tissoires <benjamin.tissoires@redhat.com>
Subject: Re: Implement per-key keyboard backlight as auxdisplay?
Message-ID: <Zar0MFelV4gY50La@duo.ucw.cz>
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Hi!

> > And while I would personally hate it, you can imagine a use case where
> > you'd like a keypress to have a visual effect around the key you
> > pressed. A kind of force feedback, if you will. I don't actually know,
> > and correct me if I'm wrong, but feels like implementing that outside of
> > the input subsystem would be non-trivial.
>=20
> Actually I think it does not belong to the input subsystem as it is,
> where the goal is to deliver keystrokes and gestures to userspace.  The
> "force feedback" kind of fits, but not really practical, again because
> of lack of geometry info. It is also not really essential to be fully
> and automatically handled by the kernel. So I think the best way is
> > to

So that's actually big question.

If the common usage is "run bad apple demo on keyboard" than pretty
clearly it should be display.

If the common usage is "computer is asking yes/no question, so
highlight yes and no buttons", then there are good arguments why input
should handle that (as it does capslock led, for example).

Actually I could imagine "real" use when shift / control /alt
backlight would indicate sticky-shift keys for handicapped.

It seems they are making mice with backlit buttons. If the main use is
highlight this key whereever it is, then it should be input.

But I suspect may use is just fancy colors and it should be display.

Best regards,
								Pavel
--=20
People of Russia, stop Putin before his war on Ukraine escalates.

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