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@nebula.com
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.
Thanks, Rafael