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Hans de Goede b7ecf663c7 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>
2017-04-27 00:02:43 +02:00
arch Merge branch 'ras-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-04-23 12:51:42 -07:00
block blk-mq: fix potential oops with polling and blk-mq scheduler 2017-04-20 14:53:28 -06:00
certs certs: Add a secondary system keyring that can be added to dynamically 2016-04-11 22:48:09 +01:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2017-04-18 09:03:50 -07:00
Documentation pci-v4.11-fixes-5 2017-04-21 09:26:34 -07:00
drivers ACPI / bus: Introduce a list of ids for "always present" devices 2017-04-27 00:02:43 +02:00
firmware WHENCE: use https://linuxtv.org for LinuxTV URLs 2015-12-04 10:35:11 -02:00
fs This pull request contains fixes for issues in both UBI and UBIFS: 2017-04-23 16:49:16 -07:00
include ACPI / bus: Introduce a list of ids for "always present" devices 2017-04-27 00:02:43 +02:00
init mm: move mm_percpu_wq initialization earlier 2017-03-31 17:13:30 -07:00
ipc Merge branch 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-03-03 10:16:38 -08:00
kernel Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-04-23 12:48:05 -07:00
lib sparc64: Use LOCKDEP_SMALL, not PROVE_LOCKING_SMALL 2017-04-18 13:11:07 -07:00
mm mm: prevent NR_ISOLATE_* stats from going negative 2017-04-20 15:30:18 -07:00
net netpoll: Check for skb->queue_mapping 2017-04-21 15:45:19 -04:00
samples statx: Include a mask for stx_attributes in struct statx 2017-04-03 01:06:00 -04:00
scripts Kbuild fixes for v4.11 2017-04-05 08:37:28 -07:00
security KEYS: fix keyctl_set_reqkey_keyring() to not leak thread keyrings 2017-04-18 15:31:49 +01:00
sound ALSA: hda - fix a problem for lineout on a Dell AIO machine 2017-03-31 10:58:26 +02:00
tools bpf: Fix values type used in test_maps 2017-04-21 15:16:46 -04:00
usr kbuild: initramfs cleanup, set target from Kconfig 2017-01-05 09:40:16 -08:00
virt KVM/ARM Fixes for v4.11-rc6 2017-04-05 16:27:47 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Merge branch 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2016-08-02 16:48:52 -04:00
.mailmap mailmap: add Martin Kepplinger's email 2017-04-13 18:24:21 -07:00
COPYING
CREDITS MAINTAINERS: Remove old e-mail address 2017-02-13 12:24:56 -05:00
Kbuild scripts/gdb: provide linux constants 2016-05-23 17:04:14 -07:00
Kconfig
MAINTAINERS bpf, doc: update bpf maintainers entry 2017-04-21 15:25:10 -04:00
Makefile Linux 4.11-rc8 2017-04-23 16:53:00 -07:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.