Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752573Ab3FIXCE (ORCPT ); Sun, 9 Jun 2013 19:02:04 -0400 Received: from cavan.codon.org.uk ([93.93.128.6]:45792 "EHLO cavan.codon.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751903Ab3FIXB7 (ORCPT ); Sun, 9 Jun 2013 19:01:59 -0400 From: Matthew Garrett To: linux-acpi@vger.kernel.org Cc: seth.forshee@canonical.com, joeyli.kernel@gmail.com, daniel.vetter@ffwll.ch, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, lenb@kernel.org, rjw@sisk.pl, Matthew Garrett Subject: [PATCH 3/3] i915: Don't provide ACPI backlight interface if firmware expects Windows 8 Date: Sun, 9 Jun 2013 19:01:39 -0400 Message-Id: <1370818899-8595-4-git-send-email-matthew.garrett@nebula.com> X-Mailer: git-send-email 1.8.2.1 In-Reply-To: <1370818899-8595-1-git-send-email-matthew.garrett@nebula.com> References: <1370818899-8595-1-git-send-email-matthew.garrett@nebula.com> X-SA-Do-Not-Run: Yes X-SA-Exim-Connect-IP: 2001:470:1f07:1371:6267:20ff:fec3:2318 X-SA-Exim-Mail-From: matthew.garrett@nebula.com X-SA-Exim-Scanned: No (on cavan.codon.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1355 Lines: 34 Windows 8 leaves backlight control up to individual graphics drivers rather than making ACPI calls itself. There's plenty of evidence to suggest that the Intel driver for Windows doesn't use the ACPI interface, including the fact that it's broken on a bunch of machines when the OS claims to support Windows 8. The simplest thing to do appears to be to disable the ACPI backlight interface on these systems. Signed-off-by: Matthew Garrett --- drivers/gpu/drm/i915/i915_dma.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c index 3b315ba..23b6292 100644 --- a/drivers/gpu/drm/i915/i915_dma.c +++ b/drivers/gpu/drm/i915/i915_dma.c @@ -1661,6 +1661,9 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags) /* Must be done after probing outputs */ intel_opregion_init(dev); acpi_video_register(); + /* Don't use ACPI backlight functions on Windows 8 platforms */ + if (acpi_osi_version() >= ACPI_OSI_WIN_8) + acpi_video_backlight_unregister(); } if (IS_GEN5(dev)) -- 1.8.2.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/