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@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.
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.
Thanks, Rafael
--- drivers/acpi/video_detect.c | 11 +++++++++-- include/linux/acpi.h | 1 + 2 files changed, 10 insertions(+), 2 deletions(-)
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_FORCE_NO_BACKLIGHT; } else { status = acpi_bus_get_device(graphics_handle, &tmp_dev); if (ACPI_FAILURE(status)) { @@ -258,13 +261,17 @@ int acpi_video_backlight_support(void) { acpi_video_caps_check();
- /* First check for boot param -> highest prio */ + /* First, check if no backlight support has been forced upon us. */ + if (acpi_video_support & ACPI_VIDEO_FORCE_NO_BACKLIGHT) + return 0; + + /* Next check for boot param -> second highest prio */ if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR) return 0; else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO) return 1;
- /* Then check for DMI blacklist -> second highest prio */ + /* Then check for DMI blacklist -> third highest prio */ if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VENDOR) return 0; else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VIDEO) Index: linux-pm/include/linux/acpi.h =================================================================== --- linux-pm.orig/include/linux/acpi.h +++ linux-pm/include/linux/acpi.h @@ -191,6 +191,7 @@ extern bool wmi_has_guid(const char *gui #define ACPI_VIDEO_BACKLIGHT_DMI_VIDEO 0x0200 #define ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VENDOR 0x0400 #define ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VIDEO 0x0800 +#define ACPI_VIDEO_FORCE_NO_BACKLIGHT 0x1000
#if defined(CONFIG_ACPI_VIDEO) || defined(CONFIG_ACPI_VIDEO_MODULE)