On Friday, July 05, 2013 11:40:02 PM Rafael J. Wysocki wrote: > On Friday, July 05, 2013 10:00:55 PM Rafael J. Wysocki wrote: > > On Friday, July 05, 2013 02:20:14 PM Rafael J. Wysocki wrote: > > > On Sunday, June 09, 2013 07:01:39 PM Matthew Garrett wrote: > > > > 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 <matthew.garrett@xxxxxxxxxx> > > > > --- > > > > 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)) > > > > > > > > > > Well, this causes build failures to happen when the ACPI video driver is > > > modular and the graphics driver is not. > > > > > > I'm not sure how to resolve that, so suggestions are welcome. > > > > Actually, that happened with the radeon patch. > > > > That said, ACPI_OSI_WIN_8 doesn't make much sense for !CONFIG_ACPI, for > > example. > > > > What about making acpi_video_register() do the quirk instead? We could add an > > argument to it indicating whether or not quirks should be applied. > > Actually, I wonder what about the appended patch (on top of the Aaron's > https://patchwork.kernel.org/patch/2812951/) instead of [1-3/3] from this series. Or even something as simple as this one. --- drivers/acpi/video_detect.c | 3 +++ 1 file changed, 3 insertions(+) Index: linux-pm/drivers/acpi/video_detect.c =================================================================== --- linux-pm.orig/drivers/acpi/video_detect.c +++ linux-pm/drivers/acpi/video_detect.c @@ -203,6 +203,9 @@ long acpi_video_get_capabilities(acpi_ha */ dmi_check_system(video_detect_dmi_table); + + if (acpi_gbl_osi_data >= ACPI_OSI_WIN_8) + acpi_video_support |= ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR; } else { status = acpi_bus_get_device(graphics_handle, &tmp_dev); if (ACPI_FAILURE(status)) { _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
