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: Mon, 14 Jul 2014 20:56:29 +0200 Message-ID: <20140714205629.130abac8@saldaea> References: <20140712180636.698e2e4c@saldaea> <20140714203422.171a3e58@saldaea> <1853509.BZhYt7FKHM@vostro.rjw.lan> <2446022.T09QX68ONu@vostro.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from mout.web.de ([212.227.15.4]:61149 "EHLO mout.web.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756640AbaGNS4c (ORCPT ); Mon, 14 Jul 2014 14:56:32 -0400 In-Reply-To: <2446022.T09QX68ONu@vostro.rjw.lan> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: "Rafael J. Wysocki" Cc: linux-acpi@vger.kernel.org, Aaron Lu 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. Cheers, Julian