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Filename Latest commit message Latest commit date
Hans de Goede 4743765bab pwm: lpss: Force runtime-resume on suspend on Cherry Trail
On Cherry Trail devices under Windows the PWM controller used for the
backlight is considered part of the GPU even though it is part of the LPSS
block and thus is an entirely different independent hardware unit.

Because of this on Cherry Trail the GPU's (GFX0 ACPI node) _PS3 and _PS0
methods save and restore the PWM controller registers.

If userspace blanks the screen before suspending, such as e.g. GNOME
does, then the PWM controller will be runtime-suspended when the suspend
starts. This causes the GFX0 _PS? methods to save a value of 0xffffffff
for the PWM control register and to restore this value on resume.

0xffffffff is not a valid value for the register and writing this causes
problems such as e.g. a flickering backlight.

This commit adds a prepare method to the dev_pm_ops and makes it return 0
on Cherry Trail devices forcing a runtime-resume before other device's
suspend methods run. This fixes the reading and writing back of 0xffffffff.

Since we now always runtime-resume the device on suspend, it will be
resumed on resume too and we no longer need to check for the GFX0 _PS0
method having resumed it underneath us, so this commit removes the now no
longer necessary complete dev_pm_op.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2018-10-16 13:15:57 +02:00
arch Merge branch 'ida-4.19' of git://git.infradead.org/users/willy/linux-dax 2018-08-26 11:48:42 -07:00
block blk-wbt: don't maintain inflight counts if disabled 2018-08-23 09:34:46 -06:00
certs export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR() 2018-08-22 23:21:44 +09:00
crypto DMAengine updates for v4.19-rc1 2018-08-18 15:55:59 -07:00
Documentation dt-bindings: pwm: tiecap: Add TI AM654 SoC specific compatible 2018-10-16 13:14:30 +02:00
drivers pwm: lpss: Force runtime-resume on suspend on Cherry Trail 2018-10-16 13:15:57 +02:00
firmware
fs Merge branch 'ida-4.19' of git://git.infradead.org/users/willy/linux-dax 2018-08-26 11:48:42 -07:00
include Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-08-26 13:39:05 -07:00
init Kbuild updates for v4.19 (2nd) 2018-08-25 13:40:38 -07:00
ipc ipc/util.c: update return value of ipc_getref from int to bool 2018-08-22 10:52:52 -07:00
kernel Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-08-26 11:25:21 -07:00
lib Merge branch 'ida-4.19' of git://git.infradead.org/users/willy/linux-dax 2018-08-26 11:48:42 -07:00
LICENSES
mm libnvdimm-for-4.19_dax-memory-failure 2018-08-25 18:43:59 -07:00
net Merge branch 'ida-4.19' of git://git.infradead.org/users/willy/linux-dax 2018-08-26 11:48:42 -07:00
samples
scripts gcc plugin fix: 2018-08-26 11:41:08 -07:00
security + Cleanups 2018-08-24 13:00:33 -07:00
sound Merge branch 'akpm' (patches from Andrew) 2018-08-23 19:20:12 -07:00
tools Merge branch 'ida-4.19' of git://git.infradead.org/users/willy/linux-dax 2018-08-26 11:48:42 -07:00
usr initramfs: move gen_initramfs_list.sh from scripts/ to usr/ 2018-08-22 23:21:44 +09:00
virt ARM: Support for Group0 interrupts in guests, Cache management 2018-08-22 13:52:44 -07:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap libnvdimm-for-4.19_misc 2018-08-25 18:13:10 -07:00
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS libnvdimm-for-4.19_misc 2018-08-25 18:13:10 -07:00
Makefile Linux 4.19-rc1 2018-08-26 14:11:59 -07:00
README

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

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

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.