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.
 
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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);

include/trace/events/power.h

@@ -7,6 +7,9 @@
 #include <linux/ktime.h>
 #include <linux/pm_qos.h>
 #include <linux/tracepoint.h>
+#include <linux/ftrace_event.h>
+
+#define TPS(x)  tracepoint_string(x)
 
 DECLARE_EVENT_CLASS(cpu,
 
@@ -90,6 +93,17 @@ TRACE_EVENT(pstate_sample,
 #define PWR_EVENT_EXIT -1
 #endif
 
+#define pm_verb_symbolic(event) \
+	__print_symbolic(event, \
+		{ PM_EVENT_SUSPEND, "suspend" }, \
+		{ PM_EVENT_RESUME, "resume" }, \
+		{ PM_EVENT_FREEZE, "freeze" }, \
+		{ PM_EVENT_QUIESCE, "quiesce" }, \
+		{ PM_EVENT_HIBERNATE, "hibernate" }, \
+		{ PM_EVENT_THAW, "thaw" }, \
+		{ PM_EVENT_RESTORE, "restore" }, \
+		{ PM_EVENT_RECOVER, "recover" })
+
 DEFINE_EVENT(cpu, cpu_frequency,
 
 	TP_PROTO(unsigned int frequency, unsigned int cpu_id),
@@ -97,58 +111,76 @@ DEFINE_EVENT(cpu, cpu_frequency,
 	TP_ARGS(frequency, cpu_id)
 );
 
-TRACE_EVENT(machine_suspend,
+TRACE_EVENT(device_pm_callback_start,
 
-	TP_PROTO(unsigned int state),
+	TP_PROTO(struct device *dev, const char *pm_ops, int event),
 
-	TP_ARGS(state),
-
-	TP_STRUCT__entry(
-		__field(	u32,		state		)
-	),
-
-	TP_fast_assign(
-		__entry->state = state;
-	),
-
-	TP_printk("state=%lu", (unsigned long)__entry->state)
-);
-
-TRACE_EVENT(device_pm_report_time,
-
-	TP_PROTO(struct device *dev, const char *pm_ops, s64 ops_time,
-		 char *pm_event_str, int error),
-
-	TP_ARGS(dev, pm_ops, ops_time, pm_event_str, error),
+	TP_ARGS(dev, pm_ops, event),
 
 	TP_STRUCT__entry(
 		__string(device, dev_name(dev))
 		__string(driver, dev_driver_string(dev))
 		__string(parent, dev->parent ? dev_name(dev->parent) : "none")
 		__string(pm_ops, pm_ops ? pm_ops : "none ")
-		__string(pm_event_str, pm_event_str)
-		__field(s64, ops_time)
+		__field(int, event)
+	),
+
+	TP_fast_assign(
+		__assign_str(device, dev_name(dev));
+		__assign_str(driver, dev_driver_string(dev));
+		__assign_str(parent,
+			dev->parent ? dev_name(dev->parent) : "none");
+		__assign_str(pm_ops, pm_ops ? pm_ops : "none ");
+		__entry->event = event;
+	),
+
+	TP_printk("%s %s, parent: %s, %s[%s]", __get_str(driver),
+		__get_str(device), __get_str(parent), __get_str(pm_ops),
+		pm_verb_symbolic(__entry->event))
+);
+
+TRACE_EVENT(device_pm_callback_end,
+
+	TP_PROTO(struct device *dev, int error),
+
+	TP_ARGS(dev, error),
+
+	TP_STRUCT__entry(
+		__string(device, dev_name(dev))
+		__string(driver, dev_driver_string(dev))
 		__field(int, error)
 	),
 
 	TP_fast_assign(
-		const char *tmp = dev->parent ? dev_name(dev->parent) : "none";
-		const char *tmp_i = pm_ops ? pm_ops : "none ";
-
 		__assign_str(device, dev_name(dev));
 		__assign_str(driver, dev_driver_string(dev));
-		__assign_str(parent, tmp);
-		__assign_str(pm_ops, tmp_i);
-		__assign_str(pm_event_str, pm_event_str);
-		__entry->ops_time = ops_time;
 		__entry->error = error;
 	),
 
-	/* ops_str has an extra space at the end */
-	TP_printk("%s %s parent=%s state=%s ops=%snsecs=%lld err=%d",
-		__get_str(driver), __get_str(device), __get_str(parent),
-		__get_str(pm_event_str), __get_str(pm_ops),
-		__entry->ops_time, __entry->error)
+	TP_printk("%s %s, err=%d",
+		__get_str(driver), __get_str(device), __entry->error)
+);
+
+TRACE_EVENT(suspend_resume,
+
+	TP_PROTO(const char *action, int val, bool start),
+
+	TP_ARGS(action, val, start),
+
+	TP_STRUCT__entry(
+		__field(const char *, action)
+		__field(int, val)
+		__field(bool, start)
+	),
+
+	TP_fast_assign(
+		__entry->action = action;
+		__entry->val = val;
+		__entry->start = start;
+	),
+
+	TP_printk("%s[%u] %s", __entry->action, (unsigned int)__entry->val,
+		(__entry->start)?"begin":"end")
 );
 
 DECLARE_EVENT_CLASS(wakeup_source,