Merge tag 'pm+acpi-3.11-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull ACPI and power management fixes from Rafael Wysocki:

 - Revert two cpuidle commits added during the 3.8 development cycle
   that turn out to have introduced a significant performance regression
   as requested by Jeremy Eder.

 - The recent patches that made the freezer less heavy-weight introduced
   a regression causing user-space-driven hibernation using the ioctl()
   interface to block indefinitely when the hibernate process executes
   try_to_freeze().  Fix from Colin Cross addresses this by adding a
   process flag to mark the hibernate/suspend process to inform the
   freezer that that process should be ignored.

 - One of the recent cpufreq reverts uncovered a problem in the core
   causing the cpufreq driver module refcount to become negative after a
   system suspend-resume cycle.  Fix from Rafael J Wysocki.

 - The evaluation of the ACPI battery _BIX method has never worked
   correctly, because the commit that added support for it forgot to
   take the "Revision" field in the return package into account.  As a
   result, the reading of battery info doesn't work at all on some
   systems, which is addressed by a fix from Lan Tianyu.

* tag 'pm+acpi-3.11-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  freezer: set PF_SUSPEND_TASK flag on tasks that call freeze_processes
  ACPI / battery: Fix parsing _BIX return value
  cpufreq: Fix cpufreq driver module refcount balance after suspend/resume
  Revert "cpuidle: Quickly notice prediction failure for repeat mode"
  Revert "cpuidle: Quickly notice prediction failure in general case"

3 files changed, 14 insertions, 8 deletions

diff --git a/kernel/freezer.c b/kernel/freezer.c
index 8b2afc1c9df0..b462fa197517 100644
--- a/kernel/freezer.c
+++ b/kernel/freezer.c
@@ -33,7 +33,7 @@ static DEFINE_SPINLOCK(freezer_lock);
  */
 bool freezing_slow_path(struct task_struct *p)
 {
-        if (p->flags & PF_NOFREEZE)
+        if (p->flags & (PF_NOFREEZE | PF_SUSPEND_TASK))
                 return false;
 
         if (pm_nosig_freezing || cgroup_freezing(p))
diff --git a/kernel/power/process.c b/kernel/power/process.c
index fc0df8486449..06ec8869dbf1 100644
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -109,6 +109,8 @@ static int try_to_freeze_tasks(bool user_only)
 
 /**
  * freeze_processes - Signal user space processes to enter the refrigerator.
+ * The current thread will not be frozen.  The same process that calls
+ * freeze_processes must later call thaw_processes.
  *
  * On success, returns 0.  On failure, -errno and system is fully thawed.
  */
@@ -120,6 +122,9 @@ int freeze_processes(void)
         if (error)
                 return error;
 
+        /* Make sure this task doesn't get frozen */
+        current->flags |= PF_SUSPEND_TASK;
+
         if (!pm_freezing)
                 atomic_inc(&system_freezing_cnt);
 
@@ -168,6 +173,7 @@ int freeze_kernel_threads(void)
 void thaw_processes(void)
 {
         struct task_struct *g, *p;
+        struct task_struct *curr = current;
 
         if (pm_freezing)
                 atomic_dec(&system_freezing_cnt);
@@ -182,10 +188,15 @@ void thaw_processes(void)
 
         read_lock(&tasklist_lock);
         do_each_thread(g, p) {
+                /* No other threads should have PF_SUSPEND_TASK set */
+                WARN_ON((p != curr) && (p->flags & PF_SUSPEND_TASK));
                 __thaw_task(p);
         } while_each_thread(g, p);
         read_unlock(&tasklist_lock);
 
+        WARN_ON(!(curr->flags & PF_SUSPEND_TASK));
+        curr->flags &= ~PF_SUSPEND_TASK;
+
         usermodehelper_enable();
 
         schedule();
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index e80183f4a6c4..e77edc97e036 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -827,13 +827,10 @@ void tick_nohz_irq_exit(void)
 {
         struct tick_sched *ts = &__get_cpu_var(tick_cpu_sched);
 
-        if (ts->inidle) {
-                /* Cancel the timer because CPU already waken up from the C-states*/
-                menu_hrtimer_cancel();
+        if (ts->inidle)
                 __tick_nohz_idle_enter(ts);
-        } else {
+        else
                 tick_nohz_full_stop_tick(ts);
-        }
 }
 
 /**
@@ -931,8 +928,6 @@ void tick_nohz_idle_exit(void)
 
         ts->inidle = 0;
 
-        /* Cancel the timer because CPU already waken up from the C-states*/
-        menu_hrtimer_cancel();
         if (ts->idle_active || ts->tick_stopped)
                 now = ktime_get();