From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Garrett Subject: Re: [PATCH] dell-wmi: Add quirk for Dell Inspiron 3138 Date: Tue, 3 Dec 2013 07:40:50 +0000 Message-ID: <20131203074050.GA323@srcf.ucam.org> References: <1386053407-7972-1-git-send-email-acelan.kao@canonical.com> <20131203070746.GA32248@srcf.ucam.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from cavan.codon.org.uk ([93.93.128.6]:52814 "EHLO cavan.codon.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751145Ab3LCHkx (ORCPT ); Tue, 3 Dec 2013 02:40:53 -0500 Content-Disposition: inline In-Reply-To: Sender: platform-driver-x86-owner@vger.kernel.org List-ID: To: AceLan Kao Cc: "platform-driver-x86@vger.kernel.org" On Tue, Dec 03, 2013 at 03:31:45PM +0800, AceLan Kao wrote: > Hi Matthew, > > Sorry, I don't understand what you mean. > > Let me explain it again. > The BIOS engineer refuse to remove the ACPI functions(_BCM) in BIOS code, > so we'll have acpi_video0 interface be created under > /sys/class/backlight/ and that interface doesn't work. > This patch is equal to add this kernel command line "acpi_backlight=vendor" > So that, there will be no acpi_video0 be create, and we will use > intel_backlight interface instead. Right. This isn't a Dell-specific problem. Windows 8 doesn't use the ACPI backlight interface, so any system that calls _OSI("Windows 2012") should use the Intel interface instead. It needs to be fixed in general, not in the platform drivers. -- Matthew Garrett | mjg59@srcf.ucam.org