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PM: Drop pm_flags that is not necessary
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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 <rjw@sisk.pl>
Acked-by: Len Brown <len.brown@intel.com>
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Rafael J. Wysocki committed Mar 14, 2011
1 parent e866500 commit 6831c6e
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Showing 5 changed files with 7 additions and 48 deletions.
5 changes: 2 additions & 3 deletions arch/x86/kernel/apm_32.c
Original file line number Diff line number Diff line change
Expand Up @@ -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>
Expand Down Expand Up @@ -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
Expand Down Expand Up @@ -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);
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22 changes: 5 additions & 17 deletions drivers/acpi/bus.c
Original file line number Diff line number Diff line change
Expand Up @@ -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");
Expand All @@ -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);
9 changes: 0 additions & 9 deletions include/linux/pm.h
Original file line number Diff line number Diff line change
Expand Up @@ -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);
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6 changes: 0 additions & 6 deletions include/linux/suspend.h
Original file line number Diff line number Diff line change
Expand Up @@ -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;

Expand All @@ -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 */

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13 changes: 0 additions & 13 deletions kernel/power/main.c
Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand Down

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