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>

1 files changed, 3 insertions, 7 deletions

diff --git a/arch/x86/kernel/apm_32.c b/arch/x86/kernel/apm_32.c
index 17089a041028..af045ca0f653 100644
--- a/arch/x86/kernel/apm_32.c
+++ b/arch/x86/kernel/apm_32.c
@@ -2256,14 +2256,12 @@ static int __init apm_init(void)
                 apm_info.disabled = 1;
                 return -ENODEV;
         }
-        if (PM_IS_ACTIVE()) {
+        if (pm_flags & PM_ACPI) {
                 printk(KERN_NOTICE "apm: overridden by ACPI.\n");
                 apm_info.disabled = 1;
                 return -ENODEV;
         }
-#ifdef CONFIG_PM_LEGACY
-        pm_active = 1;
-#endif
+        pm_flags |= PM_APM;
 
         /*
          * Set up a segment that references the real mode segment 0x40
@@ -2366,9 +2364,7 @@ static void __exit apm_exit(void)
                 kthread_stop(kapmd_task);
                 kapmd_task = NULL;
         }
-#ifdef CONFIG_PM_LEGACY
-        pm_active = 0;
-#endif
+        pm_flags &= ~PM_APM;
 }
 
 module_init(apm_init);