Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753247Ab3FYUpG (ORCPT ); Tue, 25 Jun 2013 16:45:06 -0400 Received: from smtp3-g21.free.fr ([212.27.42.3]:42359 "EHLO smtp3-g21.free.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753149Ab3FYUpB (ORCPT ); Tue, 25 Jun 2013 16:45:01 -0400 Message-ID: <1372193037.8189.24.camel@scapa> Subject: Re: [PATCH 0/3] Fix backlight issues on some Windows 8 systems From: Yves-Alexis Perez To: Matthew Garrett Cc: linux-acpi@vger.kernel.org, seth.forshee@canonical.com, joeyli.kernel@gmail.com, daniel.vetter@ffwll.ch, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, lenb@kernel.org, rjw@sisk.pl, Henrique de Moraes Holschuh Date: Tue, 25 Jun 2013 22:43:57 +0200 In-Reply-To: <20130625160848.GA27123@srcf.ucam.org> References: <1370818899-8595-1-git-send-email-matthew.garrett@nebula.com> <1371937599.17761.19.camel@scapa> <20130625160848.GA27123@srcf.ucam.org> Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-h0qekHEZ+L+n3AONK2yC" X-Mailer: Evolution 3.8.2-1 Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3337 Lines: 79 --=-h0qekHEZ+L+n3AONK2yC Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On mar., 2013-06-25 at 17:08 +0100, Matthew Garrett wrote: > On Sat, Jun 22, 2013 at 11:46:39PM +0200, Yves-Alexis Perez wrote: >=20 > > Before Linux support for acpi_osi("Windows 2012") (and when booting wit= h > > acpi_osi=3D"!Windows 2012"), brightness keys were handled by the kernel > > just fine, whether in console, in the display manager or in my desktop > > environment (Xfce). xfce4-power-manager just needs to be told that the > > brightness keys are already handled and it doesn't need to do anything. >=20 > Right, the kernel has special-casing to hook the backlight keys up to=20 > the ACPI backlight control. This is an awful thing, because there's no= =20 > way to detect this case other than parsing a single driver-specific=20 > module parameter. I'm not sure what that means. To detect what case exactly? That the brightness is handled by video.ko? >=20 > Could this functionality be duplicated across other backlight drivers?= =20 > Not easily. The ACPI driver receives keypresses and performs backlight= =20 > control. The i915 driver doesn't receive keypresses. We could easily tie= =20 > certain keycodes into backlight events, but which backlight should they= =20 > control? You're really starting to get into the kind of complex policy= =20 > decision that's best left to userspace, which is where it should have=20 > been to begin with. >=20 Well, I get the reasoning, but I'm not sure I agree. That means userspace behavior is inconsistent depending on who does it (gnome-power-manager, gnome-setting-daemon, whatever), and it usually means there's nothing handling the brightness before those are running, not to mention people not running them because they don't run a full blown desktop environment (until someone starts thinking it's a good idea to handle brightness in systemd). And in the end, the user just want the brightness keys to correctly handle the brightness, full stop. Having multiple brightness daemons using different policies on different hardware is a nightmare for the end user, imho. From a user point of view, having it handled all in the kernel works really pretty fine and is completely transparent (I have to admit that from that point of view, it was even better when it was handled by the EC but those times seem long gone). Regards, --=20 Yves-Alexis --=-h0qekHEZ+L+n3AONK2yC Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.20 (GNU/Linux) iQEcBAABCAAGBQJRygENAAoJEG3bU/KmdcCl3PgIAJWjGaTnGC4da9Pb1h4Wtyvu fGVBCqky+23sKfVovt8BjgU0asnRoZ+4pkz6QSbLlU/hVsD27m+2i0k4/bdrxOzK 2AT+SqcWXE+leObHHe181SnFC9xglXxz8HnzxzUnNoTDWuOzXdNQWNQfh5iLqaq5 Qqiiu6wNZttHzlD0Yb3ym/jtM0OuhZ/K3HHULlqOxLxOuHqDuvbFIW03+MJPrq0L HYNR5SGb+NQER9h4CCx1pS8VO+86ofB4a7QicjOSWALAG+mgBdOzCbP43q4GJncU R+IUHtO4piTArTo3ckfI2Yc78jz4kzj7CqyeS+jBpxXtMjvBbA8Z5rHJM8auePk= =ddvU -----END PGP SIGNATURE----- --=-h0qekHEZ+L+n3AONK2yC-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/