cpufreq: pcc-cpufreq: Fix wait_event() under spinlock

Fix the following bug introduced by commit 8fec051eea73 (cpufreq:
Convert existing drivers to use cpufreq_freq_transition_{begin|end})
that forgot to move the spin_lock() in pcc_cpufreq_target() past
cpufreq_freq_transition_begin() which calls wait_event():

BUG: sleeping function called from invalid context at drivers/cpufreq/cpufreq.c:370
in_atomic(): 1, irqs_disabled(): 0, pid: 2636, name: modprobe
Preemption disabled at:[<ffffffffa04d74d7>] pcc_cpufreq_target+0x27/0x200 [pcc_cpufreq]
[   51.025044]
CPU: 57 PID: 2636 Comm: modprobe Tainted: G            E  3.17.0-default #7
Hardware name: Hewlett-Packard ProLiant DL980 G7, BIOS P66 07/07/2010
 00000000ffffffff ffff88026c46b828 ffffffff81589dbd 0000000000000000
 ffff880037978090 ffff88026c46b848 ffffffff8108e1df ffff880037978090
 0000000000000000 ffff88026c46b878 ffffffff8108e298 ffff88026d73ec00
Call Trace:
 [<ffffffff81589dbd>] dump_stack+0x4d/0x90
 [<ffffffff8108e1df>] ___might_sleep+0x10f/0x180
 [<ffffffff8108e298>] __might_sleep+0x48/0xd0
 [<ffffffff8145b905>] cpufreq_freq_transition_begin+0x75/0x140 drivers/cpufreq/cpufreq.c:370 wait_event(policy->transition_wait, !policy->transition_ongoing);
 [<ffffffff8108fc99>] ? preempt_count_add+0xb9/0xc0
 [<ffffffffa04d7513>] pcc_cpufreq_target+0x63/0x200 [pcc_cpufreq] drivers/cpufreq/pcc-cpufreq.c:207 spin_lock(&pcc_lock);
 [<ffffffff810e0d0f>] ? update_ts_time_stats+0x7f/0xb0
 [<ffffffff8145be55>] __cpufreq_driver_target+0x85/0x170
 [<ffffffff8145e4c8>] od_check_cpu+0xa8/0xb0
 [<ffffffff8145ef10>] dbs_check_cpu+0x180/0x1d0
 [<ffffffff8145f310>] cpufreq_governor_dbs+0x3b0/0x720
 [<ffffffff8145ebe3>] od_cpufreq_governor_dbs+0x33/0xe0
 [<ffffffff814593d9>] __cpufreq_governor+0xa9/0x210
 [<ffffffff81459fb2>] cpufreq_set_policy+0x1e2/0x2e0
 [<ffffffff8145a6cc>] cpufreq_init_policy+0x8c/0x110
 [<ffffffff8145c9a0>] ? cpufreq_update_policy+0x1b0/0x1b0
 [<ffffffff8108fb99>] ? preempt_count_sub+0xb9/0x100
 [<ffffffff8145c6c6>] __cpufreq_add_dev+0x596/0x6b0
 [<ffffffffa016c608>] ? pcc_cpufreq_probe+0x4b4/0x4b4 [pcc_cpufreq]
 [<ffffffff8145c7ee>] cpufreq_add_dev+0xe/0x10
 [<ffffffff81408e81>] subsys_interface_register+0xc1/0xf0
 [<ffffffff8108fb99>] ? preempt_count_sub+0xb9/0x100
 [<ffffffff8145b3d7>] cpufreq_register_driver+0x117/0x2a0
 [<ffffffffa016c65d>] pcc_cpufreq_init+0x55/0x9f8 [pcc_cpufreq]
 [<ffffffffa016c608>] ? pcc_cpufreq_probe+0x4b4/0x4b4 [pcc_cpufreq]
 [<ffffffff81000298>] do_one_initcall+0xc8/0x1f0
 [<ffffffff811a731d>] ? __vunmap+0x9d/0x100
 [<ffffffff810eb9a0>] do_init_module+0x30/0x1b0
 [<ffffffff810edfa6>] load_module+0x686/0x710
 [<ffffffff810ebb20>] ? do_init_module+0x1b0/0x1b0
 [<ffffffff810ee1db>] SyS_init_module+0x9b/0xc0
 [<ffffffff8158f7a9>] system_call_fastpath+0x16/0x1b

Fixes: 8fec051eea73 (cpufreq: Convert existing drivers to use cpufreq_freq_transition_{begin|end})
Reported-and-tested-by: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: 3.15+ <stable@vger.kernel.org> # 3.15+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
cpufreq: integrator: fix integrator_cpufreq_remove return type

When building this driver as a module, we get a helpful warning
about the return type:

drivers/cpufreq/integrator-cpufreq.c:232:2: warning: initialization from incompatible pointer type
  .remove = __exit_p(integrator_cpufreq_remove),

If the remove callback returns void, the caller gets an undefined
value as it expects an integer to be returned. This fixes the
problem by passing down the value from cpufreq_unregister_driver.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPI / i915: Update the condition to ignore firmware backlight change request

Some of the Thinkpads' firmware will issue a backlight change request
through i915 operation region unconditionally on AC plug/unplug, the
backlight level used is arbitrary and thus should be ignored. This is
handled by commit 0b9f7d93ca61 (ACPI / i915: ignore firmware requests
for backlight change). Then there is a Dell laptop whose vendor backlight
interface also makes use of operation region to change backlight level
and with the above commit, that interface no long works. The condition
used to ignore the backlight change request from firmware is thus
changed to: if the vendor backlight interface is not in use and the ACPI
backlight interface is broken, we ignore the requests; oterwise, we keep
processing them.

Fixes: 0b9f7d93ca61 (ACPI / i915: ignore firmware requests for backlight change)
Link: https://lkml.org/lkml/2014/9/23/854
Reported-and-tested-by: Pali Rohár <pali.rohar@gmail.com>
Cc: 3.16+ <stable@vger.kernel.org> # 3.16+
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Acked-by: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
cpufreq: update 'cpufreq_suspended' after stopping governors

Commit 8e30444e1530 ("cpufreq: fix cpufreq suspend/resume for intel_pstate")
introduced a bug where the governors wouldn't be stopped anymore for
->target{_index}() drivers during suspend. This happens because
'cpufreq_suspended' is updated before stopping the governors during suspend
and due to this __cpufreq_governor() would return early due to this check:

	/* Don't start any governor operations if we are entering suspend */
	if (cpufreq_suspended)
		return 0;

Fixes: 8e30444e1530 ("cpufreq: fix cpufreq suspend/resume for intel_pstate")
Cc: 3.15+ <stable@vger.kernel.org> # 3.15+: 8e30444e1530 "cpufreq: fix cpufreq suspend/resume for intel_pstate"
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Merge branches 'pm-cpufreq' and 'acpi-video'

* pm-cpufreq:
  cpufreq: update 'cpufreq_suspended' after stopping governors
  cpufreq: integrator: fix integrator_cpufreq_remove return type
  cpufreq: pcc-cpufreq: Fix wait_event() under spinlock

* acpi-video:
  ACPI / i915: Update the condition to ignore firmware backlight change request
Merge tag 'pm+acpi-3.17-final' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull ACPI and power management fixes from Rafael Wysocki:
 "These are three regression fixes (cpufreq core, pcc-cpufreq, i915 /
  ACPI) and one trivial fix for a callback return value mismatch in the
  cpufreq integrator driver.

  Specifics:

   - A recent cpufreq core fix went too far and introduced a regression
     in the system suspend code path.  Fix from Viresh Kumar.

   - An ACPI-related commit in the i915 driver that fixed backlight
     problems for some Thinkpads inadvertently broke a Dell machine (in
     3.16).  Fix from Aaron Lu.

   - The pcc-cpufreq driver was broken during the 3.15 cycle by a commit
     that put wait_event() under a spinlock by mistake.  Fix that
     (Rafael J Wysocki).

   - The return value type of integrator_cpufreq_remove() is void, but
     should be int.  Fix from Arnd Bergmann"

* tag 'pm+acpi-3.17-final' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  cpufreq: update 'cpufreq_suspended' after stopping governors
  ACPI / i915: Update the condition to ignore firmware backlight change request
  cpufreq: integrator: fix integrator_cpufreq_remove return type
  cpufreq: pcc-cpufreq: Fix wait_event() under spinlock