From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jani Nikula Subject: Re: [REGRESSION BISECTED] backlight control stops workin with 3.14 and later Date: Fri, 22 Aug 2014 09:48:24 +0300 Message-ID: <87d2btm347.fsf@intel.com> References: <53CE07D9.3090308@redhat.com> <53CF7651.4080305@redhat.com> <87d2c4qzdf.fsf@intel.com> <53ED11DD.3040104@sikken.nl> <878umpq36f.fsf@intel.com> <53F06B65.4090001@sikken.nl> <87wqa6nt91.fsf@intel.com> <7955720e6579951f4da64388ab4e1673.squirrel@webmail1.one.com> <87iolohakj.fsf@intel.com> <53F66849.4010608@sikken.nl> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mga03.intel.com (mga03.intel.com [143.182.124.21]) by gabe.freedesktop.org (Postfix) with ESMTP id C78FE6E1C0 for ; Thu, 21 Aug 2014 23:50:34 -0700 (PDT) In-Reply-To: <53F66849.4010608@sikken.nl> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" To: Bertrik Sikken Cc: "intel-gfx@lists.freedesktop.org" List-Id: intel-gfx@lists.freedesktop.org On Fri, 22 Aug 2014, Bertrik Sikken wrote: > On 19-8-2014 3:29, Jani Nikula wrote: >> On Tue, 19 Aug 2014, Bertrik Sikken wrote: >>>> On Sun, 17 Aug 2014, Bertrik Sikken wrote: >>>>> On 15-8-2014 3:43, Jani Nikula wrote: >>>>>> On Thu, 14 Aug 2014, Bertrik Sikken wrote: >>>>> >>>>>>> Attached is dmesg output from booting kernel 3.14-2 (debian unstable) >>>>>>> with drm.debug=0xe and the samsung_laptop module enabled, from my >>>>>>> Samsung N150plus netbook. >>>>>> >>>>>> Have you tried 3.15? >>>>> >>>>> I've built the v3.15 kernel (using the .config file from debian >>>>> unstable and doing make oldconfig). >>>>> >>>>> The backlight is at maximum brightness after boot and I can't control >>>>> it using the backlight buttons, nor by writing to >>>>> /sys/class/backlight/samsung/brightness >>>>> (say half the value or 1/10th of max_brightness) >>>>> >>>>> Backlight does work when writing >>>>> /sys/class/backlight/intel_backlight/brightness >>>> >>>> How about disabling samsung backlight module with 3.15? >>> >>> I'm not sure what you mean by that. >>> >>> As I understand it, there are three ways to control the backlight on this >>> netbook: using intel_backlight, samsung_laptop (using a "sabi" interface) >>> and acpi_video. >>> Backlight control using the samsung_laptop driver no longer seems to work >>> after the change. If I disable it (e.g. by blacklisting it), I expect it >>> to no longer work at all obviously. >>> >>> What do you want me to test exactly? >> >> If the intel_backlight interface works in 3.15, I presume the problem is >> that you have a non-functional samsung backlight interface that is >> preferred over intel_backlight by your userspace. > > I tested the intel_backlight interface in linux v3.15 with the samsung > backlight module blacklisted. The intel_backlight interface still works. I read that as, "I no longer have problems with backlight". Jani. > > Regards, > Bertrik -- Jani Nikula, Intel Open Source Technology Center