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>

drivers/acpi/bus.c

@@ -29,7 +29,6 @@
 #include <linux/list.h>
 #include <linux/sched.h>
 #include <linux/pm.h>
-#include <linux/pm_legacy.h>
 #include <linux/device.h>
 #include <linux/proc_fs.h>
 #ifdef CONFIG_X86
@@ -764,16 +763,14 @@ static int __init acpi_init(void)
 	result = acpi_bus_init();
 
 	if (!result) {
-#ifdef CONFIG_PM_LEGACY
-		if (!PM_IS_ACTIVE())
-			pm_active = 1;
+		if (!(pm_flags & PM_APM))
+			pm_flags |= PM_ACPI;
 		else {
 			printk(KERN_INFO PREFIX
 			       "APM is already active, exiting\n");
 			disable_acpi();
 			result = -ENODEV;
 		}
-#endif
 	} else
 		disable_acpi();