More ACPI and power management updates for 3.16-rc1

- I didn't remember correctly that the Hans de Goede's ACPI video
    patches actually didn't flip the video.use_native_backlight
    default, although we had discussed that and decided to do that.
    Since I said we would do that in the previous PM+ACPI pull
    request, make that change for real now.
 
  - ACPI bus check notifications for PCI host bridges don't cause
    the bus below the host bridge to be checked for changes as they
    should because of a mistake in the ACPI-based PCI hotplug (ACPIPHP)
    subsystem that forgets to add hotplug contexts to PCI host bridge
    ACPI device objects.  Create hotplug contexts for PCI host bridges
    too as appropriate.
 
  - Revert recent cpufreq commit related to the big.LITTLE cpufreq
    driver that breaks arm64 builds.
 
  - Fix for a regression in the ppc-corenet cpufreq driver introduced
    during the 3.15 cycle and causing the driver to use the remainder
    from do_div instead of the quotient.  From Ed Swarthout.
 
  - Resets triggered by panic activate a BUG_ON() in vmalloc.c on
    systems where the ACPI reset register is located in memory address
    space.  Fix from Randy Wright.
 
  - Fix for a problem with cpufreq governors that decisions made by
    them may be suboptimal due to the fact that deferrable timers are
    used by them for CPU load sampling.  From Srivatsa S Bhat.
 
  - Fix for a problem with the Tegra cpufreq driver where the CPU
    frequency is temporarily switched to a "stable" level that
    is different from both the initial and target frequencies
    during transitions which causes udelay() to expire earlier than
    it should sometimes.  From Viresh Kumar.
 
  - New trace points and rework of some existing trace points for
    system suspend/resume profiling from Todd Brandt.
 
  - Assorted cpufreq fixes and cleanups from Stratos Karafotis and
    Viresh Kumar.
 
  - Copyright notice update for suspend-and-cpuhotplug.txt from
    Srivatsa S Bhat.
 
 /
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v2.0.22 (GNU/Linux)
 
 iQIcBAABCAAGBQJTmeBNAAoJEILEb/54YlRxFo0QAIfp74wZO9ZPcrR+6IO1AEUb
 1qcVJYMFWvisG2JO9b7DUtxwgWHk8/NMgKv+bYxUAEni95mY7PqDTdJ+Qjk7DinJ
 jVo+mzooaQg+KYGQ503YOtqsGhNFM3lE6Jw01wbLytTCetkNCkTgr//7btBbyRKn
 13Ut3o2vH9n5EMoe1jql96onJH6AfBDEn7jc5Sk4rGL7MtKAMsWNTNSGVyLFA98l
 sghO8ZR0AqnBzoedr1eBxzo6ujUqjfYlIcxowZycpJJVX02eN+KGUbOJao2+6RB+
 J6wu/FoPv2VtJkNwSB8IMgZfqceecSIXeWBG5xC22cYbSQ/IDW2k72V+kLHUqd36
 LhlYLIsIxJQovqOgPdKeP5o6OVFd4EheWBiCfNBrmYU+x2av6I6ZjTscz3Robaxh
 AVG6yU8XR2GOpoVGW/+L7R2jZ1Qse1Io0r93hXvCsSXgMkq9HbueX3mZR605msfe
 liDk+fym357cKQUreSH1XF0Q79C1wpEJ6rTz0Qi6ZxkKB+dAYE3oPA+V0+cWSxbK
 WqaFjQwPtvrrduvLj5Z+qF/zRu4LXdTxiY59utBek/RoN6zUsMMpwsRCCdBfub2O
 alBOHUPRaiUywkQtqu7yP9j7iciNxEn1/tXo97b/1qC3RrOwLWOgd8dhpWe0i0Gp
 EmQkie8qCHXw5vCpaeUK
 =0lht
 -----END PGP SIGNATURE-----

Merge tag 'pm+acpi-3.16-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull more ACPI and power management updates from Rafael Wysocki:
 "These are fixups on top of the previous PM+ACPI pull request,
  regression fixes (ACPI hotplug, cpufreq ppc-corenet), other bug fixes
  (ACPI reset, cpufreq), new PM trace points for system suspend
  profiling and a copyright notice update.

  Specifics:

   - I didn't remember correctly that the Hans de Goede's ACPI video
     patches actually didn't flip the video.use_native_backlight
     default, although we had discussed that and decided to do that.
     Since I said we would do that in the previous PM+ACPI pull request,
     make that change for real now.

   - ACPI bus check notifications for PCI host bridges don't cause the
     bus below the host bridge to be checked for changes as they should
     because of a mistake in the ACPI-based PCI hotplug (ACPIPHP)
     subsystem that forgets to add hotplug contexts to PCI host bridge
     ACPI device objects.  Create hotplug contexts for PCI host bridges
     too as appropriate.

   - Revert recent cpufreq commit related to the big.LITTLE cpufreq
     driver that breaks arm64 builds.

   - Fix for a regression in the ppc-corenet cpufreq driver introduced
     during the 3.15 cycle and causing the driver to use the remainder
     from do_div instead of the quotient.  From Ed Swarthout.

   - Resets triggered by panic activate a BUG_ON() in vmalloc.c on
     systems where the ACPI reset register is located in memory address
     space.  Fix from Randy Wright.

   - Fix for a problem with cpufreq governors that decisions made by
     them may be suboptimal due to the fact that deferrable timers are
     used by them for CPU load sampling.  From Srivatsa S Bhat.

   - Fix for a problem with the Tegra cpufreq driver where the CPU
     frequency is temporarily switched to a "stable" level that is
     different from both the initial and target frequencies during
     transitions which causes udelay() to expire earlier than it should
     sometimes.  From Viresh Kumar.

   - New trace points and rework of some existing trace points for
     system suspend/resume profiling from Todd Brandt.

   - Assorted cpufreq fixes and cleanups from Stratos Karafotis and
     Viresh Kumar.

   - Copyright notice update for suspend-and-cpuhotplug.txt from
     Srivatsa S Bhat"

* tag 'pm+acpi-3.16-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI / hotplug / PCI: Add hotplug contexts to PCI host bridges
  PM / sleep: trace events for device PM callbacks
  cpufreq: cpufreq-cpu0: remove dependency on THERMAL and REGULATOR
  cpufreq: tegra: update comment for clarity
  cpufreq: intel_pstate: Remove duplicate CPU ID check
  cpufreq: Mark CPU0 driver with CPUFREQ_NEED_INITIAL_FREQ_CHECK flag
  PM / Documentation: Update copyright in suspend-and-cpuhotplug.txt
  cpufreq: governor: remove copy_prev_load from 'struct cpu_dbs_common_info'
  cpufreq: governor: Be friendly towards latency-sensitive bursty workloads
  PM / sleep: trace events for suspend/resume
  cpufreq: ppc-corenet-cpu-freq: do_div use quotient
  Revert "cpufreq: Enable big.LITTLE cpufreq driver on arm64"
  cpufreq: Tegra: implement intermediate frequency callbacks
  cpufreq: add support for intermediate (stable) frequencies
  ACPI / video: Change the default for video.use_native_backlight to 1
  ACPI: Fix bug when ACPI reset register is implemented in system memory

include/linux/cpufreq.h

@@ -75,6 +75,7 @@ struct cpufreq_policy {
 	unsigned int		max;    /* in kHz */
 	unsigned int		cur;    /* in kHz, only needed if cpufreq
 					 * governors are used */
+	unsigned int		restore_freq; /* = policy->cur before transition */
 	unsigned int		suspend_freq; /* freq to set during suspend */
 
 	unsigned int		policy; /* see above */
@@ -221,11 +222,35 @@ struct cpufreq_driver {
 
 	/* define one out of two */
 	int	(*setpolicy)	(struct cpufreq_policy *policy);
+
+	/*
+	 * On failure, should always restore frequency to policy->restore_freq
+	 * (i.e. old freq).
+	 */
 	int	(*target)	(struct cpufreq_policy *policy,	/* Deprecated */
 				 unsigned int target_freq,
 				 unsigned int relation);
 	int	(*target_index)	(struct cpufreq_policy *policy,
 				 unsigned int index);
+	/*
+	 * Only for drivers with target_index() and CPUFREQ_ASYNC_NOTIFICATION
+	 * unset.
+	 *
+	 * get_intermediate should return a stable intermediate frequency
+	 * platform wants to switch to and target_intermediate() should set CPU
+	 * to to that frequency, before jumping to the frequency corresponding
+	 * to 'index'. Core will take care of sending notifications and driver
+	 * doesn't have to handle them in target_intermediate() or
+	 * target_index().
+	 *
+	 * Drivers can return '0' from get_intermediate() in case they don't
+	 * wish to switch to intermediate frequency for some target frequency.
+	 * In that case core will directly call ->target_index().
+	 */
+	unsigned int (*get_intermediate)(struct cpufreq_policy *policy,
+					 unsigned int index);
+	int	(*target_intermediate)(struct cpufreq_policy *policy,
+				       unsigned int index);
 
 	/* should be defined, if possible */
 	unsigned int	(*get)	(unsigned int cpu);