This patch reverts one hunk of 677bd810eedce61edf15452491781ff046b92edc "ACPI video: remove output switching control", namely the removal of probing for _DOS/_DOD when searching for video devices. This is needed on some Fujitsu Laptops (at least S7110, P8010) for the ACPI backlight interface to work, as an these machines, neither ROM nor posting methods are available, and after removal of output switching, none of the caps triggers, which prevents the backlight search from being entered. Tested on a Fujitsu Lifebook S7110 and Fujitsu Lifebook P8010. This probably fixes https://bugzilla.kernel.org/show_bug.cgi?id=27312 for the people who have no entry in /sys/class/backlight. This is the complete list of public (starting with "_") methods implemented on the S7110, BIOS rev 1.34: \_SB_.PCI0.GFX0._ADR \_SB_.PCI0.GFX0._DOS \_SB_.PCI0.GFX0._DOD \_SB_.PCI0.GFX0.CRT._ADR \_SB_.PCI0.GFX0.CRT._DCS \_SB_.PCI0.GFX0.CRT._DGS \_SB_.PCI0.GFX0.CRT._DSS \_SB_.PCI0.GFX0.LCD._ADR \_SB_.PCI0.GFX0.LCD._BCL \_SB_.PCI0.GFX0.LCD._BCM \_SB_.PCI0.GFX0.LCD._BQC \_SB_.PCI0.GFX0.LCD._DCS \_SB_.PCI0.GFX0.LCD._DGS \_SB_.PCI0.GFX0.LCD._DSS \_SB_.PCI0.GFX0.LCD._PS0 \_SB_.PCI0.GFX0.LCD._PS3 \_SB_.PCI0.GFX0.TV._ADR \_SB_.PCI0.GFX0.TV._DCS \_SB_.PCI0.GFX0.TV._DGS \_SB_.PCI0.GFX0.TV._DSS \_SB_.PCI0.GFX0.DVI._ADR \_SB_.PCI0.GFX0.DVI._DCS \_SB_.PCI0.GFX0.DVI._DGS \_SB_.PCI0.GFX0.DVI._DSS Signed-off-by: Michael Karcher <kernel@xxxxxxxxxxxxxxxxxxxxxxxxxxxx> --- drivers/acpi/video_detect.c | 5 +++++ 1 files changed, 5 insertions(+), 0 deletions(-) diff --git a/drivers/acpi/video_detect.c b/drivers/acpi/video_detect.c index 42d3d72..5af3479 100644 --- a/drivers/acpi/video_detect.c +++ b/drivers/acpi/video_detect.c @@ -82,6 +82,11 @@ long acpi_is_video_device(struct acpi_device *device) if (!device) return 0; + /* Is this device able to support video switching ? */ + if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_DOD", &h_dummy)) || + ACPI_SUCCESS(acpi_get_handle(device->handle, "_DOS", &h_dummy))) + video_caps |= ACPI_VIDEO_OUTPUT_SWITCHING; + /* Is this device able to retrieve a video ROM ? */ if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_ROM", &h_dummy))) video_caps |= ACPI_VIDEO_ROM_AVAILABLE; -- 1.7.2.3 -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html