arm/dt: msm8974: Lower GPU voltage constraints

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
workqueue: perform cpu down operations from low priority cpu_notifier()

Currently, all workqueue cpu hotplug operations run off
CPU_PRI_WORKQUEUE which is higher than normal notifiers.  This is to
ensure that workqueue is up and running while bringing up a CPU before
other notifiers try to use workqueue on the CPU.

Per-cpu workqueues are supposed to remain working and bound to the CPU
for normal CPU_DOWN_PREPARE notifiers.  This holds mostly true even
with workqueue offlining running with higher priority because
workqueue CPU_DOWN_PREPARE only creates a bound trustee thread which
runs the per-cpu workqueue without concurrency management without
explicitly detaching the existing workers.

However, if the trustee needs to create new workers, it creates
unbound workers which may wander off to other CPUs while
CPU_DOWN_PREPARE notifiers are in progress.  Furthermore, if the CPU
down is cancelled, the per-CPU workqueue may end up with workers which
aren't bound to the CPU.

While reliably reproducible with a convoluted artificial test-case
involving scheduling and flushing CPU burning work items from CPU down
notifiers, this isn't very likely to happen in the wild, and, even
when it happens, the effects are likely to be hidden by the following
successful CPU down.

Fix it by using different priorities for up and down notifiers - high
priority for up operations and low priority for down operations.

Workqueue cpu hotplug operations will soon go through further cleanup.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org
Acked-by: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
backlight: fix a bug where the screen would be completely dark or near darkness with backlight_dimmer enabled when the display dimmed. The brightness level can't be any lower than dev->min_brightness and previous code allowed that to happen, so fix it.

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
backlight: clean the code.

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
Revert "ASoC: msm: change to enable audio"

This reverts commit 6bfb8bda8eb35a8570f6fd629f6bbce7ae3d90eb.
workqueue: use new hashtable implementation

Switch workqueues to use the new hashtable implementation. This reduces the
amount of generic unrelated code in the workqueues.

This patch depends on d9b482c ("hashtable: introduce a small and naive
hashtable") which was merged in v3.6.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
workqueue: fix find_worker_executing_work() brekage from hashtable conversion

commit ("workqueue: use new hashtable implementation") incorrectly
made busy workers hashed by the pointer value of worker instead of
work.  This broke find_worker_executing_work() which in turn broke a
lot of fundamental operations of workqueue - non-reentrancy and
flushing among others.  The flush malfunction triggered warning in
disk event code in Fengguang's automated test.

 write_dev_root_ (3265) used greatest stack depth: 2704 bytes left
 ------------[ cut here ]------------
 WARNING: at /c/kernel-tests/src/stable/block/genhd.c:1574 disk_clear_events+0x\
cf/0x108()
 Hardware name: Bochs
 Modules linked in:
 Pid: 3328, comm: ata_id Not tainted 3.7.0-01930-gbff6343 #1167
 Call Trace:
  [<ffffffff810997c4>] warn_slowpath_common+0x83/0x9c
  [<ffffffff810997f7>] warn_slowpath_null+0x1a/0x1c
  [<ffffffff816aea77>] disk_clear_events+0xcf/0x108
  [<ffffffff811bd8be>] check_disk_change+0x27/0x59
  [<ffffffff822e48e2>] cdrom_open+0x49/0x68b
  [<ffffffff81ab0291>] idecd_open+0x88/0xb7
  [<ffffffff811be58f>] __blkdev_get+0x102/0x3ec
  [<ffffffff811bea08>] blkdev_get+0x18f/0x30f
  [<ffffffff811bebfd>] blkdev_open+0x75/0x80
  [<ffffffff8118f510>] do_dentry_open+0x1ea/0x295
  [<ffffffff8118f5f0>] finish_open+0x35/0x41
  [<ffffffff8119c720>] do_last+0x878/0xa25
  [<ffffffff8119c993>] path_openat+0xc6/0x333
  [<ffffffff8119cf37>] do_filp_open+0x38/0x86
  [<ffffffff81190170>] do_sys_open+0x6c/0xf9
  [<ffffffff8119021e>] sys_open+0x21/0x23
  [<ffffffff82c1c3d9>] system_call_fastpath+0x16/0x1b

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
hashtable: introduce a small and naive hashtable

This hashtable implementation is using hlist buckets to provide a simple
hashtable to prevent it from getting reimplemented all over the kernel.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
[ Merging this now, so that subsystems can start applying Sasha's
  patches that use this   - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
workqueue: remove reduntant code

that ended up in kernel/workqueue.c as a result of nighlies commits.