From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans de Goede Subject: Re: [Regression]: Changing brightness does not work with v3.16-rc4 Date: Wed, 16 Jul 2014 10:35:33 +0200 Message-ID: <53C63955.2090905@redhat.com> References: <20140712180636.698e2e4c@saldaea> <53C53543.1050207@redhat.com> <53C53E89.2020505@intel.com> <2231725.PEI454q0UP@vostro.rjw.lan> <53C61BD5.8080501@redhat.com> <53C6276A.6020206@intel.com> <53C63431.7020205@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from mx1.redhat.com ([209.132.183.28]:27337 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757055AbaGPIfl (ORCPT ); Wed, 16 Jul 2014 04:35:41 -0400 In-Reply-To: <53C63431.7020205@redhat.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Aaron Lu , "Rafael J. Wysocki" Cc: Julian Wollrath , linux-acpi@vger.kernel.org Hi, On 07/16/2014 10:13 AM, Hans de Goede wrote: > I realize that this does not fix Julian's problem. As I see it there are > 2 separate problems here: > > 1) backlight control issues on Windows 8 laptops, this is what we are > trying to solve with video.use_native_backlight=1 (and without using > any acpi_osi override) > > 2) Some component in the stack needs to responds to backlight key-presses > and actually use the backlight control to change the backlight setting, > normally this is done by gnome / kde / unity / xfce, but what about users > not running those? For some of those users brightness_switch_enabled=1 > has been making things work for them, but that only works if acpi-video > controls the backlight, which it does not do everywhere, and which we > want to get away from for Windows 8 laptops since it is just too broken > there. > > Note that 2. is not limited to Windows 8 laptops / acpi-video in any > way, we've 23 non acpi-video backlight drivers under drivers/platform/x86/ > alone + the native gpu backlight drivers. So what we really need is a > solution for any laptop not using acpi-video for backlight control and > not running one of the big 4 desktop environments. > > Note that we pretty much have the same problem for any acpi event, > power button pressed, lid closed, etc. are all "key press" type > events typically handles by the desktop enviroment (e.g. we don't > automatically suspend on lid-close, we just tell userspace). And we already > have a solution for these type of events when running a desktop environment > which handles them, these get handled by acpid. So to me it seems that s/handles/does not handle/ small but important typo. > the obvious (and one and only right) way to fix this is to teach acpid > to deal with brightness key-presses. > > I'm willing to write a patch for acpid to implement this, and then > Julian's setup should just work without needing any special kernel > commandline options. > > Julian would that be an acceptable solution for you, and would you be > willing to test such a patch ? Regards, Hans