From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from jabberwock.ucw.cz (jabberwock.ucw.cz [46.255.230.98]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 68B892D03B; Thu, 18 Jan 2024 17:45:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=46.255.230.98 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705599942; cv=none; b=SJDmUQYshjd7ZSuHeCzea+5Wj3j0lSJloSydFfmQmgaNtZq6FSUFPPfMthUugHgdtpvNLUkDhjdi7s5E5zSYtRLI6FGEp1X/7zzz6ilQ6M+Ql/FuXveCFT3zNSOiyS1FlC17ay2J6NvALBmxmo8bZfBcj6MEswFo/B/u+n7YGx8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705599942; c=relaxed/simple; bh=RyY3iug65fvKTAhGTPkBeOA+ALdT0Buumyxgvxot7Es=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=i3DxURNUPuxgV2spdDOexF14BDySi0qpmk/v7QnUAII7jYQILKSaEIt8YivD/5Teb/lmE+t9toJNpVVOUDHbVGR+NYwooNUKIDX821Zh/yRoOogztrn+9R/x+S/CMIB2+StO+SA9q/Ob4IjfDHq/YS8+Hrg/zm5H+SY9VZerSBc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ucw.cz; spf=pass smtp.mailfrom=ucw.cz; dkim=pass (1024-bit key) header.d=ucw.cz header.i=@ucw.cz header.b=D8YVA5Wu; arc=none smtp.client-ip=46.255.230.98 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ucw.cz Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ucw.cz Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ucw.cz header.i=@ucw.cz header.b="D8YVA5Wu" Received: by jabberwock.ucw.cz (Postfix, from userid 1017) id 1B4181C007B; Thu, 18 Jan 2024 18:45:37 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ucw.cz; s=gen1; t=1705599937; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=s2decVdRnW3kcXYTXMhZ+4hppOm4DXM8+5MfDGDRqr0=; b=D8YVA5WuCkS7PJEvNxOIdAa/kR3li8rbSqVyqKK2zs7wjQsV8Yp/VEOyRtTkA+EN1vHW65 h42g8hGwRL52WcKdxl9uzxBYVMIIne5rcj6FGkBAXn91gTkWsj8rKMcLuTsIZ4ltqcn+WL bQ/UOAGQXnRNJ7mcre5KkuxaHXR1Cv4= Date: Thu, 18 Jan 2024 18:45:36 +0100 From: Pavel Machek To: Werner Sembach Cc: Hans de Goede , Jani Nikula , jikos@kernel.org, Jelle van der Waa , Miguel Ojeda , Lee Jones , linux-kernel@vger.kernel.org, "dri-devel@lists.freedesktop.org" , linux-input@vger.kernel.org, ojeda@kernel.org, linux-leds@vger.kernel.org Subject: Re: Implement per-key keyboard backlight as auxdisplay? Message-ID: References: <87sf61bm8t.fsf@intel.com> <8096a042-83bd-4b9f-b633-79e86995c9b8@redhat.com> <4222268b-ff44-4b7d-bf11-e350594bbe24@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="9D/I+LN93effYwNd" Content-Disposition: inline In-Reply-To: --9D/I+LN93effYwNd Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi! > We have an upcoming device that has a per-key keyboard backlight, but does > the control completely via a wmi/acpi interface. So no usable hidraw here > for a potential userspace driver implementation ... >=20 > So a quick summary for the ideas floating in this thread so far: >=20 > 1. Expand leds interface allowing arbitrary modes with semi arbitrary > optional attributes: > =A0=A0=A0 - Con: >=20 > =A0=A0=A0 =A0=A0=A0 - Violates the simplicity paradigm of the leds interf= ace (e.g. with > this one leds entry controls possible multiple leds) Let's not do this. > 2. Implement per-key keyboards as auxdisplay >=20 > =A0=A0=A0 - Pro: >=20 > =A0=A0=A0 =A0=A0=A0 - Already has a concept for led positions >=20 > =A0=A0=A0 =A0=A0=A0 - Is conceptually closer to "multiple leds forming a = singular entity" >=20 > =A0=A0=A0 - Con: >=20 > =A0=A0=A0 =A0=A0=A0 - No preexisting UPower support >=20 > =A0=A0=A0 =A0=A0=A0 - No concept for special hardware lightning modes >=20 > =A0=A0=A0 =A0=A0=A0 - No support for arbitrary led outlines yet (e.g. ISO= style enter-key) Please do this one. > 3. Implement in input subsystem >=20 > =A0=A0=A0 - Pro: >=20 > =A0=A0=A0 =A0=A0=A0 - Preexisting concept for keys and key purpose >=20 > =A0=A0=A0 - Con: >=20 > =A0=A0=A0 =A0=A0=A0 - Not in scope for subsystem >=20 > =A0=A0=A0 =A0=A0=A0 - No other preexisting light infrastructure Or negotiate with input people to do this. > 4. Implement a simple leds driver only supporting a small subset of the > capabilities and make it disable-able for a userspace driver to take over No. Kernel should abstract this away. Best regards, Pavel --=20 People of Russia, stop Putin before his war on Ukraine escalates. --9D/I+LN93effYwNd Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iF0EABECAB0WIQRPfPO7r0eAhk010v0w5/Bqldv68gUCZaljwAAKCRAw5/Bqldv6 8t2rAJ0bXGLlIcltuLM/IFy7NcEBaumlcwCcCEGqrSVmOZCnA82+Y9Rt7Thq3Bw= =6pEX -----END PGP SIGNATURE----- --9D/I+LN93effYwNd--