From mboxrd@z Thu Jan 1 00:00:00 1970 From: joeyli Subject: Re: [PATCH 3/3] i915: Don't provide ACPI backlight interface if firmware expects Windows 8 Date: Mon, 10 Jun 2013 17:22:23 +0800 Message-ID: <1370856143.6523.114.camel@linux-s257.site> References: <1370818899-8595-1-git-send-email-matthew.garrett@nebula.com> <1370818899-8595-4-git-send-email-matthew.garrett@nebula.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <1370818899-8595-4-git-send-email-matthew.garrett@nebula.com> Sender: linux-kernel-owner@vger.kernel.org To: Matthew Garrett Cc: linux-acpi@vger.kernel.org, seth.forshee@canonical.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 List-Id: linux-acpi@vger.kernel.org =E6=96=BC =E6=97=A5=EF=BC=8C2013-06-09 =E6=96=BC 19:01 -0400=EF=BC=8CMa= tthew Garrett =E6=8F=90=E5=88=B0=EF=BC=9A > 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, includin= g the > fact that it's broken on a bunch of machines when the OS claims to su= pport > Windows 8. The simplest thing to do appears to be to disable the ACPI > backlight interface on these systems. >=20 > Signed-off-by: Matthew Garrett > --- > drivers/gpu/drm/i915/i915_dma.c | 3 +++ > 1 file changed, 3 insertions(+) >=20 > diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i= 915_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, un= signed 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() >=3D ACPI_OSI_WIN_8) > + acpi_video_backlight_unregister(); > } > =20 > if (IS_GEN5(dev)) This patch set works to me on Acer Aspire V3 notebook for unregister th= e backlight interface of acpi video driver when i915 loaded. Acer Aspire V3 has the Windows8 support in DSDT. Tested-by: Lee, Chun-Yi Thanks a lot! Joey Lee