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Srinivas Pandruvada ad7532cefd iio: hid-sensor-trigger: Don't touch sensors unless user space requests
One of the user complained that on his system Thinkpad Yoga S1, with
commit f1664eaace ("iio: hid-sensor-trigger: Fix the race with user
space powering up sensors") causes the system to resume immediately
on suspend (S3 operation). On this system the sensor hub is on USB
and is a wake up device from S3. So if any sensor sends data on
motion, the system will wake up. This can be a legitimate use case
to wake up device motion, but that needs proper user space support
to set right thresholds.

In fact the above commit didn't cause this regression, but any operation
which cause sensors to wake up would have caused the same issue. So if
user reads the raw sensor data, same issue occurs, with or without this
commit. Only difference is that the above commit by default will trigger
a power up and power down of sensors as part of runtime pm enable
(runtime enable will cause a runtime resume callback followed by
runtime_suspend callback). Previously user has to do some action on
sensors.

On investigation it was observed that the current driver correctly
changing the state of all sensors to power off but then also some sensor
will still send some data. Only option is to never power up any sensor.

Only good option is to:
- Using sysfs interface disable USB as a wakeup device (This will not
need any driver change)

Since some user don't care about sensors. So for those users this change
brings back old functionality. As long as they don't cause any operation
to power up sensors (like raw read or start iio-sensor-proxy service),
the sensors will not be to touched. This is done by delaying run time
enable till user space does some operation with sensors.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=196853
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2017-10-14 19:29:50 +01:00
arch Merge 4.14-rc4 into staging-next 2017-10-09 09:02:35 +02:00
block bsg-lib: fix use-after-free under memory-pressure 2017-10-04 08:35:04 -06:00
certs modsign: add markers to endif-statements in certs/Makefile 2017-07-14 11:01:37 +10:00
crypto crypto: af_alg - update correct dst SGL entry 2017-09-20 17:42:42 +08:00
Documentation dt-bindings: iio: health: Use binding name for max30102 in example 2017-10-14 19:24:12 +01:00
drivers iio: hid-sensor-trigger: Don't touch sensors unless user space requests 2017-10-14 19:29:50 +01:00
firmware firmware: Restore support for built-in firmware 2017-09-16 10:58:48 -07:00
fs Changes since last update: 2017-10-06 15:53:36 -07:00
include iio: hid-sensor-trigger: Don't touch sensors unless user space requests 2017-10-14 19:29:50 +01:00
init Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-09-14 18:54:01 -07:00
ipc fix a typo in put_compat_shm_info() 2017-09-25 20:41:46 -04:00
kernel Merge branch 'core-watchdog-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-10-06 08:36:41 -07:00
lib lib/ratelimit.c: use deferred printk() version 2017-10-03 17:54:26 -07:00
mm mm/memory_hotplug: define find_{smallest|biggest}_section_pfn as unsigned long 2017-10-03 17:54:26 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-10-05 08:40:09 -07:00
samples media updates for v4.14-rc1 2017-09-07 12:53:14 -07:00
scripts checkpatch: fix ignoring cover-letter logic 2017-10-03 17:54:26 -07:00
security lsm: fix smack_inode_removexattr and xattr_getsecurity memleak 2017-10-04 18:03:15 +11:00
sound sound fixes for 4.14-rc4 2017-10-05 10:39:29 -07:00
tools Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-10-01 12:06:31 -07:00
usr ramfs: clarify help text that compression applies to ramfs as well as legacy ramdisk. 2017-07-06 16:24:30 -07:00
virt Revert "KVM: Don't accept obviously wrong gsi values via KVM_IRQFD" 2017-09-19 08:37:17 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support to generate LLVM assembly files 2017-04-25 08:13:52 +09:00
.mailmap Update James Hogan's email address 2017-10-04 17:11:53 -07:00
COPYING
CREDITS selinux/stable-4.14 PR 20170831 2017-09-12 13:21:00 -07:00
Kbuild kbuild: Consolidate header generation from ASM offset information 2017-04-13 05:43:37 +09:00
Kconfig kbuild: migrate all arch to the kconfig mainmenu upgrade 2010-09-19 22:54:11 -04:00
MAINTAINERS ARC udpates for 4.14-rc4 2017-10-06 15:57:08 -07:00
Makefile Linux 4.14-rc4 2017-10-08 20:53:29 -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.