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>

include/linux/pm.h

@@ -246,6 +246,15 @@ static inline int call_platform_enable_wakeup(struct device *dev, int is_on)
 		device_set_wakeup_enable(dev,val); \
 	} while(0)
 
+/*
+ * Global Power Management flags
+ * Used to keep APM and ACPI from both being active
+ */
+extern unsigned int	pm_flags;
+
+#define PM_APM	1
+#define PM_ACPI	2
+
 #endif /* __KERNEL__ */
 
 #endif /* _LINUX_PM_H */