On some x86 systems the DSDT hides APCI devices to work around Windows
driver bugs. On one such system the device is even hidden until a certain
time after _SB.PCI0.GFX0.LCD.LCD1._ON gets called has passed *and*
_STA has been called at least 3 times since. TL;DR: it is a mess.
Until now the always_present_id matching was used to force status
for a whole class of devices, e.g. always enable PWM1 on CHerry Trail
devices.
This commit extends the always_present_id matching code to optionally
also check for a DMI match so that we can also add system specific
quirks to the always_present_id array.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The INT0002 device is necessary to clear wakeup interrupt sources
on Cherry Trail devices, without it we get nobody cared IRQ msgs
and some systems don't properly resume at all without it.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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>
Hans de Goede