From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754998Ab3LHNrf (ORCPT ); Sun, 8 Dec 2013 08:47:35 -0500 Received: from nm36-vm0.bullet.mail.bf1.yahoo.com ([72.30.238.136]:20050 "HELO nm36-vm0.bullet.mail.bf1.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1753522Ab3LHNrd convert rfc822-to-8bit (ORCPT ); Sun, 8 Dec 2013 08:47:33 -0500 X-Greylist: delayed 421 seconds by postgrey-1.27 at vger.kernel.org; Sun, 08 Dec 2013 08:47:33 EST X-Yahoo-Newman-Property: ymail-3 X-Yahoo-Newman-Id: 463723.79272.bm@omp1022.mail.bf1.yahoo.com DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=X-YMail-OSG:Received:X-Rocket-MIMEInfo:X-Mailer:Message-ID:Date:From:Reply-To:Subject:To:MIME-Version:Content-Type:Content-Transfer-Encoding; b=G1+POU66UK0CGcR0RSyXoeXO8eYW9wS1GaEEnQdkzLOMIpFOveQeJi5ZrCGZLsm7iBIX8lWEBL7s0Mf2VxRY9tGtq8OB8RrncSCTuQnVq8p+roVb00qu/yn7c3/TFAvaHpI2rpDrretWbwxJA/nRw0IPoZwl+QOqnM2ablSoGpw=; X-YMail-OSG: nyL1I.AVM1l.11JA19tcHCO8phseoqMHxP2ffmytK0R6YiV jXr_aKSb8tkrBcM47EaTQgAW6CGOUpU6xl_RdwggnZmZjLUzdhPgH7Zk3iXb iCNdoAlC2DeDVOanznbhxpBBJd2vw7j8_g0gu8vv852h_VrZXi7mzSJXxC7g 0ZsnOwgfcT4rCel6AKUybJl4oQhm9O4MAjBgn0EGQuuVYoEey9O0rsUWrvpR Tp_C1Tl9JvQA8OIBhW8iajorTbopp7P4Xca6YmJ2itg9aODkegxjPZw2vdX8 kaqJWkI7TCjQXFEsI9C6sn3YyOYWRkAS8ciuQDKGSjkcZeOSxtT0TFvnHE4W qUtmPCWcJMGRNNULC9_4Gqb0726Uvyb2Z5Wkcho356o2wBNAr0In9oUqc0BH SDG3ct.8vDU0p1JP5WSTLHSIYpIytVSuNRj8t1nHocc6EAWtYJfOwqxP9eey anAlV9hm5ZbfZnb1QrsMiavdVFbo3rNclMfYd87TkocofsRx_bzMUkeX7xky ITwyfHIlPa6yc.DYliqJXX9Rzfjg_qxXNppC7k0yzNdts8d3i3L7lncjkgn2 mMOypetAoOIkt X-Rocket-MIMEInfo: 002.001,SSBoYXZlIGEgRGVsbCBJbnNwaXJvbiBONzAxMCBMYXB0b3Agd2l0aCBJbnRlbCBncmFwaGljcy4gV2hlbiB0aGUgZGVsbC1sYXB0b3AgbW9kdWxlIGlzIGxvYWRlZCwKdHdvIGJhY2tsaWdodCBkZXZpY2UgZGV2aWNlcyBhcmUgY3JlYXRlZDsgZGVsbF9iYWNrbGlnaHQsIGFuZCBpbnRlbF9iYWNrbGlnaHQgZnJvbSB0aGUgSW50ZWwKZ3JhcGhpY3MgZHJpdmVyLiBUaGUgZGVsbF9iYWNrbGlnaHQgZGV2aWNlIGlzIG5vbi1mdW5jdGlvbmFsLCBidXQgdGhlIGdyYXBoaWNzIHN1YnN5c3RlbSB1c2VzCml0IGluc3QBMAEBAQE- X-Mailer: YahooMailWebService/0.8.169.609 Message-ID: <1386510031.81267.YahooMailNeo@web160401.mail.bf1.yahoo.com> Date: Sun, 8 Dec 2013 05:40:31 -0800 (PST) From: Alex Davis Reply-To: Alex Davis Subject: [PATCH] dell-laptop: add parameter to disable the backlight device. To: "mjg59@srcf.ucam.org" , "linux-kernel@vger.kernel.org" MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org I have a Dell Inspiron N7010 Laptop with Intel graphics. When the dell-laptop module is loaded, two backlight device devices are created; dell_backlight, and intel_backlight from the Intel graphics driver. The dell_backlight device is non-functional, but the graphics subsystem uses it instead of the functioning intel_backlight device. The result is that, when running KDE, screen brightness cannot be controlled. I've added a module parameter, disable_backlight which, when true, will disable the dell_backlight device, and leave only the intel_backlight: with this, screen brightness can be controlled. This patch is against 3.10. Signed-off-by: Alex Davis --- dell-laptop.c.orig    2013-12-01 19:05:39.693149050 -0500 +++ dell-laptop.c    2013-12-01 17:29:27.613372482 -0500 @@ -35,6 +35,9 @@  /* This structure will be modified by the firmware when we enter   * system management mode, hence the volatiles */   +static bool disable_backlight; +module_param(disable_backlight, bool, 0644); +  struct calling_interface_buffer {      u16 class;      u16 select; @@ -561,6 +564,9 @@ static int __init dell_init(void)        dell_laptop_dir = debugfs_create_dir("dell_laptop", NULL);   +    if (disable_backlight) +        return 0; +  #ifdef CONFIG_ACPI      /* In the event of an ACPI backlight being available, don't       * register the platform controller.   I code, therefore I am