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authorHans de Goede <hdegoede@redhat.com>2017-04-21 13:47:40 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2017-04-27 01:02:43 +0300
commitb7ecf663c75eed1e764f57281f9508c49c18516e (patch)
tree61c77533f0e4676219c5137d601e8765c894f4cd /drivers/acpi/Makefile
parent5a7ad1146caa895ad718a534399e38bd2ba721b7 (diff)
downloadlinux-b7ecf663c75eed1e764f57281f9508c49c18516e.tar.xz
ACPI / bus: Introduce a list of ids for "always present" devices
Several Bay / Cherry Trail devices (all of which ship with Windows 10) hide the LPSS PWM controller in ACPI, typically the _STA method looks like this: Method (_STA, 0, NotSerialized) // _STA: Status { If (OSID == One) { Return (Zero) } Return (0x0F) } Where OSID is some dark magic seen in all Cherry Trail ACPI tables making the machine behave differently depending on which OS it *thinks* it is booting, this gets set in a number of ways which we cannot control, on some newer machines it simple hardcoded to "One" aka win10. This causes the PWM controller to get hidden, which means Linux cannot control the backlight level on cht based tablets / laptops. Since loading the driver for this does no harm (the only in kernel user of it is the i915 driver, which will only uses it when it needs it), this commit makes acpi_bus_get_status() always set status to ACPI_STA_DEFAULT for the LPSS PWM device, fixing the lack of backlight control. Signed-off-by: Hans de Goede <hdegoede@redhat.com> [ rjw: Rename the new file to utils.c ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/acpi/Makefile')
-rw-r--r--drivers/acpi/Makefile1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index d94f92f88ca1..2a81d278bcf3 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -50,6 +50,7 @@ acpi-$(CONFIG_ACPI_REDUCED_HARDWARE_ONLY) += evged.o
acpi-y += sysfs.o
acpi-y += property.o
acpi-$(CONFIG_X86) += acpi_cmos_rtc.o
+acpi-$(CONFIG_X86) += x86/utils.o
acpi-$(CONFIG_DEBUG_FS) += debugfs.o
acpi-$(CONFIG_ACPI_NUMA) += numa.o
acpi-$(CONFIG_ACPI_PROCFS_POWER) += cm_sbs.o