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: Tue, 19 Aug 2014 16:29:32 +0300 Message-ID: <87iolohakj.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> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by gabe.freedesktop.org (Postfix) with ESMTP id 329A16E5C8 for ; Tue, 19 Aug 2014 06:29:41 -0700 (PDT) In-Reply-To: <7955720e6579951f4da64388ab4e1673.squirrel@webmail1.one.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Cc: "intel-gfx@lists.freedesktop.org" , Bertrik Sikken List-Id: intel-gfx@lists.freedesktop.org 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. BR, Jani. > > Kind regards, > Bertrik > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Jani Nikula, Intel Open Source Technology Center