PM: ACPI and APM must not be enabled at the same time

patch 9f9adecd2d0e4f88fa0e8cb06c6ec207748df70a in mainline.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/arch/i386/kernel/apm.c b/arch/i386/kernel/apm.c
index f02a8aca826be21abc18ac3e31fe8a59caeebb9e..14dc1118614009e204d81d53434c615d577580d8 100644 (file)
--- a/arch/i386/kernel/apm.c
+++ b/arch/i386/kernel/apm.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);

diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index 9ba778a2b484ee1601f53ebd6ccd8278741784f0..222fcec2f96749e8a64c5a143590171817d64205 100644 (file)
--- a/drivers/acpi/bus.c
+++ b/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
@@ -757,16 +756,14 @@ 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();
 

diff --git a/include/linux/pm.h b/include/linux/pm.h
index 48b71badfb4c837969fedf91f90cba2cce369587..71e589b8aad6bde683e100e042d0e125009463f7 100644 (file)
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -344,6 +344,15 @@ 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 */

diff --git a/include/linux/pm_legacy.h b/include/linux/pm_legacy.h
index 514729a446888e21dee4289db2ea4e71f80f6eaa..446f4f42b952894b3ffe1c2cb2cf91780e86ee33 100644 (file)
--- a/include/linux/pm_legacy.h
+++ b/include/linux/pm_legacy.h
@@ -4,10 +4,6 @@
 
 #ifdef CONFIG_PM_LEGACY
 
-extern int pm_active;
-
-#define PM_IS_ACTIVE() (pm_active != 0)
-
 /*
  * Register a device with power management
  */
@@ -21,8 +17,6 @@ int __deprecated pm_send_all(pm_request_t rqst, void *data);
 
 #else /* CONFIG_PM_LEGACY */
 
-#define PM_IS_ACTIVE() 0
-
 static inline struct pm_dev *pm_register(pm_dev_t type,
                                         unsigned long id,
                                         pm_callback callback)

diff --git a/kernel/power/main.c b/kernel/power/main.c
index 350b485b3b60bdc7679cbd9963ef4ba4b64ed4f3..0e445341ab30b25bd1879c57c716fbfecd035cb5 100644 (file)
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -27,6 +27,9 @@ BLOCKING_NOTIFIER_HEAD(pm_chain_head);
 
 DEFINE_MUTEX(pm_mutex);
 
+unsigned int pm_flags;
+EXPORT_SYMBOL(pm_flags);
+
 #ifdef CONFIG_SUSPEND
 
 /* This is just an arbitrary number */

diff --git a/kernel/power/pm.c b/kernel/power/pm.c
index c50d15266c1096d42d61e296ea4da13d34cb57ec..60c73fa670d5a65b38f454c941201a22b7d4bf35 100644 (file)
--- a/kernel/power/pm.c
+++ b/kernel/power/pm.c
@@ -27,8 +27,6 @@
 #include <linux/interrupt.h>
 #include <linux/mutex.h>
 
-int pm_active;
-
 /*
  *     Locking notes:
  *             pm_devs_lock can be a semaphore providing pm ops are not called
@@ -204,6 +202,4 @@ int pm_send_all(pm_request_t rqst, void *data)
 
 EXPORT_SYMBOL(pm_register);
 EXPORT_SYMBOL(pm_send_all);
-EXPORT_SYMBOL(pm_active);
-