PM: ACPI and APM must not be enabled at the same time

ACPI and APM used "pm_active" to guarantee that
they would not be simultaneously active.

But pm_active was recently moved under CONFIG_PM_LEGACY,
so that without CONFIG_PM_LEGACY, pm_active became a NOP --
allowing ACPI and APM to both be simultaneously enabled.
This caused unpredictable results, including boot hangs.

Further, the code under CONFIG_PM_LEGACY is scheduled
for removal.

So replace pm_active with pm_flags.
pm_flags depends only on CONFIG_PM,
which is present for both CONFIG_APM and CONFIG_ACPI.

http://bugzilla.kernel.org/show_bug.cgi?id=9194

Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

2 files changed, 3 insertions, 4 deletions

diff --git a/kernel/power/main.c b/kernel/power/main.c
index 3cdf95b1dc92..f71c9504a5c5 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -28,6 +28,9 @@ BLOCKING_NOTIFIER_HEAD(pm_chain_head);
 
 DEFINE_MUTEX(pm_mutex);
 
+unsigned int pm_flags;
+EXPORT_SYMBOL(pm_flags);
+
 #ifdef CONFIG_SUSPEND
 
 /* This is just an arbitrary number */
diff --git a/kernel/power/pm.c b/kernel/power/pm.c
index c50d15266c10..60c73fa670d5 100644
--- a/kernel/power/pm.c
+++ b/kernel/power/pm.c
@@ -27,8 +27,6 @@
 #include <linux/interrupt.h>
 #include <linux/mutex.h>
 
-int pm_active;
-
 /*
  *      Locking notes:
  *              pm_devs_lock can be a semaphore providing pm ops are not called
@@ -204,6 +202,4 @@ int pm_send_all(pm_request_t rqst, void *data)
 
 EXPORT_SYMBOL(pm_register);
 EXPORT_SYMBOL(pm_send_all);
-EXPORT_SYMBOL(pm_active);
-