From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161777Ab2GLXfp (ORCPT ); Thu, 12 Jul 2012 19:35:45 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:58752 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755625Ab2GLWjw (ORCPT ); Thu, 12 Jul 2012 18:39:52 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg KH , torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Igor Murzov , Zhang Rui , Len Brown Subject: [ 075/187] ACPI video: Still use ACPI backlight control if _DOS doesnt exist Date: Thu, 12 Jul 2012 15:33:51 -0700 Message-Id: <20120712191529.373756326@linuxfoundation.org> X-Mailer: git-send-email 1.7.10.1.362.g242cab3 In-Reply-To: <20120712191522.742634173@linuxfoundation.org> References: <20120712192421.GA28926@kroah.com> <20120712191522.742634173@linuxfoundation.org> User-Agent: quilt/0.60-20.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Greg KH 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Zhang Rui commit b03738430c7537d5f87948e0b35d8aaf2688c6b4 upstream. This fixes a regression in 3.4-rc1 caused by commit ea9f8856bd6d4ed45885b06a338f7362cd6c60e5 (ACPI video: Harden video bus adding.) Some platforms don't have _DOS control method, but the ACPI backlight still works. We should not invoke _DOS for these platforms. https://bugzilla.kernel.org/show_bug.cgi?id=43168 Cc: Igor Murzov Signed-off-by: Zhang Rui Signed-off-by: Len Brown Signed-off-by: Greg Kroah-Hartman --- drivers/acpi/video.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/acpi/video.c +++ b/drivers/acpi/video.c @@ -558,6 +558,8 @@ acpi_video_bus_DOS(struct acpi_video_bus union acpi_object arg0 = { ACPI_TYPE_INTEGER }; struct acpi_object_list args = { 1, &arg0 }; + if (!video->cap._DOS) + return 0; if (bios_flag < 0 || bios_flag > 3 || lcd_flag < 0 || lcd_flag > 1) return -EINVAL;