From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julian Wollrath Subject: Re: [Regression]: Changing brightness does not work with v3.16-rc4 Date: Wed, 16 Jul 2014 13:36:29 +0200 Message-ID: <20140716133629.4b6d19c4@saldaea> References: <20140712180636.698e2e4c@saldaea> <20140714203422.171a3e58@saldaea> <1853509.BZhYt7FKHM@vostro.rjw.lan> <2446022.T09QX68ONu@vostro.rjw.lan> <20140714205629.130abac8@saldaea> <53C5E548.8000905@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from mout.web.de ([212.227.17.12]:61730 "EHLO mout.web.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756244AbaGPLgc (ORCPT ); Wed, 16 Jul 2014 07:36:32 -0400 In-Reply-To: <53C5E548.8000905@intel.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Aaron Lu Cc: "Rafael J. Wysocki" , linux-acpi@vger.kernel.org Am Wed, 16 Jul 2014 10:36:56 +0800 schrieb Aaron Lu : > On 07/15/2014 02:56 AM, Julian Wollrath wrote: > > Am Mon, 14 Jul 2014 21:10:47 +0200 > > schrieb "Rafael J. Wysocki" : > > > >> On Monday, July 14, 2014 09:02:34 PM Rafael J. Wysocki wrote: > >>> On Monday, July 14, 2014 08:34:22 PM Julian Wollrath wrote: > >>>> Am Mon, 14 Jul 2014 20:21:19 +0200 > >>>> schrieb "Rafael J. Wysocki" : > >>>> > >>>>> On Saturday, July 12, 2014 06:24:52 PM Julian Wollrath wrote: > >>>>>> Hi, > >>>>>> > >>>>>>> changing the brightness on my Thinkpad X230 with Intel > >>>>>>> HD4000 graphics, stopped working after commit 886129a8eebe > >>>>>>> (ACPI / video: change acpi-video brightness_switch_enabled > >>>>>>> default to 0). Changing it back to 1, fixes the problem, if > >>>>>>> "acpi_osi=!Windows 2012" is also set. Before that commit > >>>>>>> just setting "acpi_osi=!Windows 2012" was enough to get > >>>>>>> changing the brightness working. > >>>>>> > >>>>>> small correction: It setting "acpi_osi=!Windows 2012" does > >>>>>> only help when using a kernel with commit 886129a8eebe as > >>>>>> HEAD, with v3.16-rc4 setting > >>>>>> video.brightness_switch_enabled=1 and acpi_osi=!Windows 2012 > >>>>>> or just one of them, does not make changing the brightness > >>>>>> work again. > >>>>> > >>>>> And reverting commit 751109aad583 (ACPI / video: Change the > >>>>> default for video.use_native_backlight to 1) make that last > >>>>> problem go away, right? > >>>>> > >>>>> We are going to rever commit 886129a8eebe for other reasons, so > >>>>> can you please revert it from 3.16-rc5 on your system and > >>>>> report back? > >>>> Yes, with both 751109aad583 and 886129a8eebe reverted, changing > >>>> the brightness works again. > >>> > >>> What if you revert 886129a8eebe alone? > >> > >> I mean, what exactly do you need to pass to the kernel command line > >> in that case to make brightness switching work? > > I need to pass > > acpi_osi="!Windows 2012" video.brightness_switch_enabled=1 > > video.use_native_backlight=-1 > > > > If I leave one of these parameters out, the brightness switch stops > > working. > > If you only pass the following 2 cmdline options: > acpi_osi="!Windows 2012" video.brightness_switch_enabled=1 > Will there be the /sys/class/backlight/acpi_videoX file? Yes, and interestingly with v3.16-rc5 the brightness switching works with just these two options. Cheers, Julian