PM: Drop pm_flags that is not necessary

The variable pm_flags is used to prevent APM from being enabled
along with ACPI, which would lead to problems.  However, acpi_init()
is always called before apm_init() and after acpi_init() has
returned, it is known whether or not ACPI will be used.  Namely, if
acpi_disabled is not set after acpi_init() has returned, this means
that ACPI is enabled.  Thus, it is sufficient to check acpi_disabled
in apm_init() to prevent APM from being enabled in parallel with
ACPI.

Signed-off-by: Rafael J. Wysocki <[email protected]>
Acked-by: Len Brown <[email protected]>

Author: rjwysocki

arch/x86/kernel/apm_32.c

@@ -227,6 +227,7 @@
 #include <linux/suspend.h>
 #include <linux/kthread.h>
 #include <linux/jiffies.h>
+#include <linux/acpi.h>
 
 #include <asm/system.h>
 #include <asm/uaccess.h>
@@ -2331,12 +2332,11 @@ static int __init apm_init(void)
 		apm_info.disabled = 1;
 		return -ENODEV;
 	}
-	if (pm_flags & PM_ACPI) {
+	if (!acpi_disabled) {
 		printk(KERN_NOTICE "apm: overridden by ACPI.\n");
 		apm_info.disabled = 1;
 		return -ENODEV;
 	}
-	pm_flags |= PM_APM;
 
 	/*
 	 * Set up the long jump entry point to the APM BIOS, which is called
@@ -2428,7 +2428,6 @@ static void __exit apm_exit(void)
 		kthread_stop(kapmd_task);
 		kapmd_task = NULL;
 	}
-	pm_flags &= ~PM_APM;
 }
 
 module_init(apm_init);

drivers/acpi/bus.c

@@ -1007,8 +1007,7 @@ struct kobject *acpi_kobj;
 
 static int __init acpi_init(void)
 {
-	int result = 0;
-
+	int result;
 
 	if (acpi_disabled) {
 		printk(KERN_INFO PREFIX "Interpreter disabled.\n");
@@ -1023,29 +1022,18 @@ static int __init acpi_init(void)
 
 	init_acpi_device_notify();
 	result = acpi_bus_init();
-
-	if (!result) {
-		pci_mmcfg_late_init();
-		if (pm_apm_enabled()) {
-			printk(KERN_INFO PREFIX
-			       "APM is already active, exiting\n");
-			disable_acpi();
-			result = -ENODEV;
-		} else {
-			pm_set_acpi_flag();
-		}
-	} else
+	if (result) {
 		disable_acpi();
-
-	if (acpi_disabled)
 		return result;
+	}
 
+	pci_mmcfg_late_init();
 	acpi_scan_init();
 	acpi_ec_init();
 	acpi_debugfs_init();
 	acpi_sleep_proc_init();
 	acpi_wakeup_device_init();
-	return result;
+	return 0;
 }
 
 subsys_initcall(acpi_init);

include/linux/pm.h

@@ -565,15 +565,6 @@ enum dpm_order {
 	DPM_ORDER_DEV_LAST,
 };
 
-/*
- * 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
-
 extern int pm_generic_suspend(struct device *dev);
 extern int pm_generic_resume(struct device *dev);
 extern int pm_generic_freeze(struct device *dev);

include/linux/suspend.h

@@ -272,9 +272,6 @@ extern int unregister_pm_notifier(struct notifier_block *nb);
 	register_pm_notifier(&fn##_nb);			\
 }
 
-extern bool pm_apm_enabled(void);
-extern void pm_set_acpi_flag(void);
-
 /* drivers/base/power/wakeup.c */
 extern bool events_check_enabled;
 
@@ -295,9 +292,6 @@ static inline int unregister_pm_notifier(struct notifier_block *nb)
 
 #define pm_notifier(fn, pri)	do { (void)(fn); } while (0)
 
-static inline bool pm_apm_enabled(void) { return false; }
-static inline void pm_set_acpi_flag(void) {}
-
 static inline bool pm_wakeup_pending(void) { return false; }
 #endif /* !CONFIG_PM_SLEEP */
 

kernel/power/main.c

@@ -19,19 +19,6 @@ DEFINE_MUTEX(pm_mutex);
 
 #ifdef CONFIG_PM_SLEEP
 
-unsigned int pm_flags;
-EXPORT_SYMBOL(pm_flags);
-
-bool pm_apm_enabled(void)
-{
-	return !!(pm_flags & PM_APM);
-}
-
-void pm_set_acpi_flag(void)
-{
-	pm_flags |= PM_ACPI;
-}
-
 /* Routines for PM-transition notifications */
 
 static BLOCKING_NOTIFIER_HEAD(pm_chain_head);