[Xen-devel] [PATCH 27/44] x86: apm: Register with kernel poweroff handler

[Guenter Roeck <linux@xxxxxxxxxxxx>]

Register with kernel poweroff handler instead of setting pm_power_off
directly. Register with high priority value of 192 to reflect that
the original code overwrites existing poweroff handlers.

Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Jiri Kosina <jkosina@xxxxxxx>
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
---
 arch/x86/kernel/apm_32.c | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/apm_32.c b/arch/x86/kernel/apm_32.c
index 5848744..84566a6 100644
--- a/arch/x86/kernel/apm_32.c
+++ b/arch/x86/kernel/apm_32.c
@@ -219,6 +219,7 @@
 #include <linux/init.h>
 #include <linux/time.h>
 #include <linux/sched.h>
+#include <linux/notifier.h>
 #include <linux/pm.h>
 #include <linux/capability.h>
 #include <linux/device.h>
@@ -981,7 +982,8 @@ recalc:
  *     on their first cpu.
  */
 
-static void apm_power_off(void)
+static int apm_power_off(struct notifier_block *this, unsigned long unused1,
+                        void *unused2)
 {
        /* Some bioses don't like being called from CPU != 0 */
        if (apm_info.realmode_power_off) {
@@ -990,8 +992,14 @@ static void apm_power_off(void)
        } else {
                (void)set_system_power_state(APM_STATE_OFF);
        }
+       return NOTIFY_DONE;
 }
 
+static struct notifier_block apm_poweroff_nb = {
+       .notifier_call = apm_power_off,
+       .priority = 192,
+};
+
 #ifdef CONFIG_APM_DO_ENABLE
 
 /**
@@ -1847,8 +1855,11 @@ static int apm(void *unused)
        }
 
        /* Install our power off handler.. */
-       if (power_off)
-               pm_power_off = apm_power_off;
+       if (power_off) {
+               error = register_poweroff_handler(&apm_poweroff_nb);
+               if (error)
+                       pr_err("apm: Failed to register poweroff handler\n");
+       }
 
        if (num_online_cpus() == 1 || smp) {
 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
@@ -2408,9 +2419,8 @@ static void __exit apm_exit(void)
                        apm_error("disengage power management", error);
        }
        misc_deregister(&apm_device);
+       unregister_poweroff_handler(&apm_poweroff_nb);
        remove_proc_entry("apm", NULL);
-       if (power_off)
-               pm_power_off = NULL;
        if (kapmd_task) {
                kthread_stop(kapmd_task);
                kapmd_task = NULL;
-- 
1.9.1


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