Merge branch 'llseek' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl
[linux-2.6.git] / drivers / char / apm-emulation.c
1 /*
2  * bios-less APM driver for ARM Linux
3  *  Jamey Hicks <jamey@crl.dec.com>
4  *  adapted from the APM BIOS driver for Linux by Stephen Rothwell (sfr@linuxcare.com)
5  *
6  * APM 1.2 Reference:
7  *   Intel Corporation, Microsoft Corporation. Advanced Power Management
8  *   (APM) BIOS Interface Specification, Revision 1.2, February 1996.
9  *
10  * [This document is available from Microsoft at:
11  *    http://www.microsoft.com/hwdev/busbios/amp_12.htm]
12  */
13 #include <linux/module.h>
14 #include <linux/poll.h>
15 #include <linux/slab.h>
16 #include <linux/mutex.h>
17 #include <linux/proc_fs.h>
18 #include <linux/seq_file.h>
19 #include <linux/miscdevice.h>
20 #include <linux/apm_bios.h>
21 #include <linux/capability.h>
22 #include <linux/sched.h>
23 #include <linux/suspend.h>
24 #include <linux/apm-emulation.h>
25 #include <linux/freezer.h>
26 #include <linux/device.h>
27 #include <linux/kernel.h>
28 #include <linux/list.h>
29 #include <linux/init.h>
30 #include <linux/completion.h>
31 #include <linux/kthread.h>
32 #include <linux/delay.h>
33
34 #include <asm/system.h>
35
36 /*
37  * The apm_bios device is one of the misc char devices.
38  * This is its minor number.
39  */
40 #define APM_MINOR_DEV   134
41
42 /*
43  * See Documentation/Config.help for the configuration options.
44  *
45  * Various options can be changed at boot time as follows:
46  * (We allow underscores for compatibility with the modules code)
47  *      apm=on/off                      enable/disable APM
48  */
49
50 /*
51  * Maximum number of events stored
52  */
53 #define APM_MAX_EVENTS          16
54
55 struct apm_queue {
56         unsigned int            event_head;
57         unsigned int            event_tail;
58         apm_event_t             events[APM_MAX_EVENTS];
59 };
60
61 /*
62  * thread states (for threads using a writable /dev/apm_bios fd):
63  *
64  * SUSPEND_NONE:        nothing happening
65  * SUSPEND_PENDING:     suspend event queued for thread and pending to be read
66  * SUSPEND_READ:        suspend event read, pending acknowledgement
67  * SUSPEND_ACKED:       acknowledgement received from thread (via ioctl),
68  *                      waiting for resume
69  * SUSPEND_ACKTO:       acknowledgement timeout
70  * SUSPEND_DONE:        thread had acked suspend and is now notified of
71  *                      resume
72  *
73  * SUSPEND_WAIT:        this thread invoked suspend and is waiting for resume
74  *
75  * A thread migrates in one of three paths:
76  *      NONE -1-> PENDING -2-> READ -3-> ACKED -4-> DONE -5-> NONE
77  *                                  -6-> ACKTO -7-> NONE
78  *      NONE -8-> WAIT -9-> NONE
79  *
80  * While in PENDING or READ, the thread is accounted for in the
81  * suspend_acks_pending counter.
82  *
83  * The transitions are invoked as follows:
84  *      1: suspend event is signalled from the core PM code
85  *      2: the suspend event is read from the fd by the userspace thread
86  *      3: userspace thread issues the APM_IOC_SUSPEND ioctl (as ack)
87  *      4: core PM code signals that we have resumed
88  *      5: APM_IOC_SUSPEND ioctl returns
89  *
90  *      6: the notifier invoked from the core PM code timed out waiting
91  *         for all relevant threds to enter ACKED state and puts those
92  *         that haven't into ACKTO
93  *      7: those threads issue APM_IOC_SUSPEND ioctl too late,
94  *         get an error
95  *
96  *      8: userspace thread issues the APM_IOC_SUSPEND ioctl (to suspend),
97  *         ioctl code invokes pm_suspend()
98  *      9: pm_suspend() returns indicating resume
99  */
100 enum apm_suspend_state {
101         SUSPEND_NONE,
102         SUSPEND_PENDING,
103         SUSPEND_READ,
104         SUSPEND_ACKED,
105         SUSPEND_ACKTO,
106         SUSPEND_WAIT,
107         SUSPEND_DONE,
108 };
109
110 /*
111  * The per-file APM data
112  */
113 struct apm_user {
114         struct list_head        list;
115
116         unsigned int            suser: 1;
117         unsigned int            writer: 1;
118         unsigned int            reader: 1;
119
120         int                     suspend_result;
121         enum apm_suspend_state  suspend_state;
122
123         struct apm_queue        queue;
124 };
125
126 /*
127  * Local variables
128  */
129 static DEFINE_MUTEX(apm_mutex);
130 static atomic_t suspend_acks_pending = ATOMIC_INIT(0);
131 static atomic_t userspace_notification_inhibit = ATOMIC_INIT(0);
132 static int apm_disabled;
133 static struct task_struct *kapmd_tsk;
134
135 static DECLARE_WAIT_QUEUE_HEAD(apm_waitqueue);
136 static DECLARE_WAIT_QUEUE_HEAD(apm_suspend_waitqueue);
137
138 /*
139  * This is a list of everyone who has opened /dev/apm_bios
140  */
141 static DECLARE_RWSEM(user_list_lock);
142 static LIST_HEAD(apm_user_list);
143
144 /*
145  * kapmd info.  kapmd provides us a process context to handle
146  * "APM" events within - specifically necessary if we're going
147  * to be suspending the system.
148  */
149 static DECLARE_WAIT_QUEUE_HEAD(kapmd_wait);
150 static DEFINE_SPINLOCK(kapmd_queue_lock);
151 static struct apm_queue kapmd_queue;
152
153 static DEFINE_MUTEX(state_lock);
154
155 static const char driver_version[] = "1.13";    /* no spaces */
156
157
158
159 /*
160  * Compatibility cruft until the IPAQ people move over to the new
161  * interface.
162  */
163 static void __apm_get_power_status(struct apm_power_info *info)
164 {
165 }
166
167 /*
168  * This allows machines to provide their own "apm get power status" function.
169  */
170 void (*apm_get_power_status)(struct apm_power_info *) = __apm_get_power_status;
171 EXPORT_SYMBOL(apm_get_power_status);
172
173
174 /*
175  * APM event queue management.
176  */
177 static inline int queue_empty(struct apm_queue *q)
178 {
179         return q->event_head == q->event_tail;
180 }
181
182 static inline apm_event_t queue_get_event(struct apm_queue *q)
183 {
184         q->event_tail = (q->event_tail + 1) % APM_MAX_EVENTS;
185         return q->events[q->event_tail];
186 }
187
188 static void queue_add_event(struct apm_queue *q, apm_event_t event)
189 {
190         q->event_head = (q->event_head + 1) % APM_MAX_EVENTS;
191         if (q->event_head == q->event_tail) {
192                 static int notified;
193
194                 if (notified++ == 0)
195                     printk(KERN_ERR "apm: an event queue overflowed\n");
196                 q->event_tail = (q->event_tail + 1) % APM_MAX_EVENTS;
197         }
198         q->events[q->event_head] = event;
199 }
200
201 static void queue_event(apm_event_t event)
202 {
203         struct apm_user *as;
204
205         down_read(&user_list_lock);
206         list_for_each_entry(as, &apm_user_list, list) {
207                 if (as->reader)
208                         queue_add_event(&as->queue, event);
209         }
210         up_read(&user_list_lock);
211         wake_up_interruptible(&apm_waitqueue);
212 }
213
214 static ssize_t apm_read(struct file *fp, char __user *buf, size_t count, loff_t *ppos)
215 {
216         struct apm_user *as = fp->private_data;
217         apm_event_t event;
218         int i = count, ret = 0;
219
220         if (count < sizeof(apm_event_t))
221                 return -EINVAL;
222
223         if (queue_empty(&as->queue) && fp->f_flags & O_NONBLOCK)
224                 return -EAGAIN;
225
226         wait_event_interruptible(apm_waitqueue, !queue_empty(&as->queue));
227
228         while ((i >= sizeof(event)) && !queue_empty(&as->queue)) {
229                 event = queue_get_event(&as->queue);
230
231                 ret = -EFAULT;
232                 if (copy_to_user(buf, &event, sizeof(event)))
233                         break;
234
235                 mutex_lock(&state_lock);
236                 if (as->suspend_state == SUSPEND_PENDING &&
237                     (event == APM_SYS_SUSPEND || event == APM_USER_SUSPEND))
238                         as->suspend_state = SUSPEND_READ;
239                 mutex_unlock(&state_lock);
240
241                 buf += sizeof(event);
242                 i -= sizeof(event);
243         }
244
245         if (i < count)
246                 ret = count - i;
247
248         return ret;
249 }
250
251 static unsigned int apm_poll(struct file *fp, poll_table * wait)
252 {
253         struct apm_user *as = fp->private_data;
254
255         poll_wait(fp, &apm_waitqueue, wait);
256         return queue_empty(&as->queue) ? 0 : POLLIN | POLLRDNORM;
257 }
258
259 /*
260  * apm_ioctl - handle APM ioctl
261  *
262  * APM_IOC_SUSPEND
263  *   This IOCTL is overloaded, and performs two functions.  It is used to:
264  *     - initiate a suspend
265  *     - acknowledge a suspend read from /dev/apm_bios.
266  *   Only when everyone who has opened /dev/apm_bios with write permission
267  *   has acknowledge does the actual suspend happen.
268  */
269 static long
270 apm_ioctl(struct file *filp, u_int cmd, u_long arg)
271 {
272         struct apm_user *as = filp->private_data;
273         int err = -EINVAL;
274
275         if (!as->suser || !as->writer)
276                 return -EPERM;
277
278         mutex_lock(&apm_mutex);
279         switch (cmd) {
280         case APM_IOC_SUSPEND:
281                 mutex_lock(&state_lock);
282
283                 as->suspend_result = -EINTR;
284
285                 switch (as->suspend_state) {
286                 case SUSPEND_READ:
287                         /*
288                          * If we read a suspend command from /dev/apm_bios,
289                          * then the corresponding APM_IOC_SUSPEND ioctl is
290                          * interpreted as an acknowledge.
291                          */
292                         as->suspend_state = SUSPEND_ACKED;
293                         atomic_dec(&suspend_acks_pending);
294                         mutex_unlock(&state_lock);
295
296                         /*
297                          * suspend_acks_pending changed, the notifier needs to
298                          * be woken up for this
299                          */
300                         wake_up(&apm_suspend_waitqueue);
301
302                         /*
303                          * Wait for the suspend/resume to complete.  If there
304                          * are pending acknowledges, we wait here for them.
305                          */
306                         freezer_do_not_count();
307
308                         wait_event(apm_suspend_waitqueue,
309                                    as->suspend_state == SUSPEND_DONE);
310
311                         /*
312                          * Since we are waiting until the suspend is done, the
313                          * try_to_freeze() in freezer_count() will not trigger
314                          */
315                         freezer_count();
316                         break;
317                 case SUSPEND_ACKTO:
318                         as->suspend_result = -ETIMEDOUT;
319                         mutex_unlock(&state_lock);
320                         break;
321                 default:
322                         as->suspend_state = SUSPEND_WAIT;
323                         mutex_unlock(&state_lock);
324
325                         /*
326                          * Otherwise it is a request to suspend the system.
327                          * Just invoke pm_suspend(), we'll handle it from
328                          * there via the notifier.
329                          */
330                         as->suspend_result = pm_suspend(PM_SUSPEND_MEM);
331                 }
332
333                 mutex_lock(&state_lock);
334                 err = as->suspend_result;
335                 as->suspend_state = SUSPEND_NONE;
336                 mutex_unlock(&state_lock);
337                 break;
338         }
339         mutex_unlock(&apm_mutex);
340
341         return err;
342 }
343
344 static int apm_release(struct inode * inode, struct file * filp)
345 {
346         struct apm_user *as = filp->private_data;
347
348         filp->private_data = NULL;
349
350         down_write(&user_list_lock);
351         list_del(&as->list);
352         up_write(&user_list_lock);
353
354         /*
355          * We are now unhooked from the chain.  As far as new
356          * events are concerned, we no longer exist.
357          */
358         mutex_lock(&state_lock);
359         if (as->suspend_state == SUSPEND_PENDING ||
360             as->suspend_state == SUSPEND_READ)
361                 atomic_dec(&suspend_acks_pending);
362         mutex_unlock(&state_lock);
363
364         wake_up(&apm_suspend_waitqueue);
365
366         kfree(as);
367         return 0;
368 }
369
370 static int apm_open(struct inode * inode, struct file * filp)
371 {
372         struct apm_user *as;
373
374         mutex_lock(&apm_mutex);
375         as = kzalloc(sizeof(*as), GFP_KERNEL);
376         if (as) {
377                 /*
378                  * XXX - this is a tiny bit broken, when we consider BSD
379                  * process accounting. If the device is opened by root, we
380                  * instantly flag that we used superuser privs. Who knows,
381                  * we might close the device immediately without doing a
382                  * privileged operation -- cevans
383                  */
384                 as->suser = capable(CAP_SYS_ADMIN);
385                 as->writer = (filp->f_mode & FMODE_WRITE) == FMODE_WRITE;
386                 as->reader = (filp->f_mode & FMODE_READ) == FMODE_READ;
387
388                 down_write(&user_list_lock);
389                 list_add(&as->list, &apm_user_list);
390                 up_write(&user_list_lock);
391
392                 filp->private_data = as;
393         }
394         mutex_unlock(&apm_mutex);
395
396         return as ? 0 : -ENOMEM;
397 }
398
399 static const struct file_operations apm_bios_fops = {
400         .owner          = THIS_MODULE,
401         .read           = apm_read,
402         .poll           = apm_poll,
403         .unlocked_ioctl = apm_ioctl,
404         .open           = apm_open,
405         .release        = apm_release,
406         .llseek         = noop_llseek,
407 };
408
409 static struct miscdevice apm_device = {
410         .minor          = APM_MINOR_DEV,
411         .name           = "apm_bios",
412         .fops           = &apm_bios_fops
413 };
414
415
416 #ifdef CONFIG_PROC_FS
417 /*
418  * Arguments, with symbols from linux/apm_bios.h.
419  *
420  *   0) Linux driver version (this will change if format changes)
421  *   1) APM BIOS Version.  Usually 1.0, 1.1 or 1.2.
422  *   2) APM flags from APM Installation Check (0x00):
423  *      bit 0: APM_16_BIT_SUPPORT
424  *      bit 1: APM_32_BIT_SUPPORT
425  *      bit 2: APM_IDLE_SLOWS_CLOCK
426  *      bit 3: APM_BIOS_DISABLED
427  *      bit 4: APM_BIOS_DISENGAGED
428  *   3) AC line status
429  *      0x00: Off-line
430  *      0x01: On-line
431  *      0x02: On backup power (BIOS >= 1.1 only)
432  *      0xff: Unknown
433  *   4) Battery status
434  *      0x00: High
435  *      0x01: Low
436  *      0x02: Critical
437  *      0x03: Charging
438  *      0x04: Selected battery not present (BIOS >= 1.2 only)
439  *      0xff: Unknown
440  *   5) Battery flag
441  *      bit 0: High
442  *      bit 1: Low
443  *      bit 2: Critical
444  *      bit 3: Charging
445  *      bit 7: No system battery
446  *      0xff: Unknown
447  *   6) Remaining battery life (percentage of charge):
448  *      0-100: valid
449  *      -1: Unknown
450  *   7) Remaining battery life (time units):
451  *      Number of remaining minutes or seconds
452  *      -1: Unknown
453  *   8) min = minutes; sec = seconds
454  */
455 static int proc_apm_show(struct seq_file *m, void *v)
456 {
457         struct apm_power_info info;
458         char *units;
459
460         info.ac_line_status = 0xff;
461         info.battery_status = 0xff;
462         info.battery_flag   = 0xff;
463         info.battery_life   = -1;
464         info.time           = -1;
465         info.units          = -1;
466
467         if (apm_get_power_status)
468                 apm_get_power_status(&info);
469
470         switch (info.units) {
471         default:        units = "?";    break;
472         case 0:         units = "min";  break;
473         case 1:         units = "sec";  break;
474         }
475
476         seq_printf(m, "%s 1.2 0x%02x 0x%02x 0x%02x 0x%02x %d%% %d %s\n",
477                      driver_version, APM_32_BIT_SUPPORT,
478                      info.ac_line_status, info.battery_status,
479                      info.battery_flag, info.battery_life,
480                      info.time, units);
481
482         return 0;
483 }
484
485 static int proc_apm_open(struct inode *inode, struct file *file)
486 {
487         return single_open(file, proc_apm_show, NULL);
488 }
489
490 static const struct file_operations apm_proc_fops = {
491         .owner          = THIS_MODULE,
492         .open           = proc_apm_open,
493         .read           = seq_read,
494         .llseek         = seq_lseek,
495         .release        = single_release,
496 };
497 #endif
498
499 static int kapmd(void *arg)
500 {
501         do {
502                 apm_event_t event;
503
504                 wait_event_interruptible(kapmd_wait,
505                                 !queue_empty(&kapmd_queue) || kthread_should_stop());
506
507                 if (kthread_should_stop())
508                         break;
509
510                 spin_lock_irq(&kapmd_queue_lock);
511                 event = 0;
512                 if (!queue_empty(&kapmd_queue))
513                         event = queue_get_event(&kapmd_queue);
514                 spin_unlock_irq(&kapmd_queue_lock);
515
516                 switch (event) {
517                 case 0:
518                         break;
519
520                 case APM_LOW_BATTERY:
521                 case APM_POWER_STATUS_CHANGE:
522                         queue_event(event);
523                         break;
524
525                 case APM_USER_SUSPEND:
526                 case APM_SYS_SUSPEND:
527                         pm_suspend(PM_SUSPEND_MEM);
528                         break;
529
530                 case APM_CRITICAL_SUSPEND:
531                         atomic_inc(&userspace_notification_inhibit);
532                         pm_suspend(PM_SUSPEND_MEM);
533                         atomic_dec(&userspace_notification_inhibit);
534                         break;
535                 }
536         } while (1);
537
538         return 0;
539 }
540
541 static int apm_suspend_notifier(struct notifier_block *nb,
542                                 unsigned long event,
543                                 void *dummy)
544 {
545         struct apm_user *as;
546         int err;
547
548         /* short-cut emergency suspends */
549         if (atomic_read(&userspace_notification_inhibit))
550                 return NOTIFY_DONE;
551
552         switch (event) {
553         case PM_SUSPEND_PREPARE:
554                 /*
555                  * Queue an event to all "writer" users that we want
556                  * to suspend and need their ack.
557                  */
558                 mutex_lock(&state_lock);
559                 down_read(&user_list_lock);
560
561                 list_for_each_entry(as, &apm_user_list, list) {
562                         if (as->suspend_state != SUSPEND_WAIT && as->reader &&
563                             as->writer && as->suser) {
564                                 as->suspend_state = SUSPEND_PENDING;
565                                 atomic_inc(&suspend_acks_pending);
566                                 queue_add_event(&as->queue, APM_USER_SUSPEND);
567                         }
568                 }
569
570                 up_read(&user_list_lock);
571                 mutex_unlock(&state_lock);
572                 wake_up_interruptible(&apm_waitqueue);
573
574                 /*
575                  * Wait for the the suspend_acks_pending variable to drop to
576                  * zero, meaning everybody acked the suspend event (or the
577                  * process was killed.)
578                  *
579                  * If the app won't answer within a short while we assume it
580                  * locked up and ignore it.
581                  */
582                 err = wait_event_interruptible_timeout(
583                         apm_suspend_waitqueue,
584                         atomic_read(&suspend_acks_pending) == 0,
585                         5*HZ);
586
587                 /* timed out */
588                 if (err == 0) {
589                         /*
590                          * Move anybody who timed out to "ack timeout" state.
591                          *
592                          * We could time out and the userspace does the ACK
593                          * right after we time out but before we enter the
594                          * locked section here, but that's fine.
595                          */
596                         mutex_lock(&state_lock);
597                         down_read(&user_list_lock);
598                         list_for_each_entry(as, &apm_user_list, list) {
599                                 if (as->suspend_state == SUSPEND_PENDING ||
600                                     as->suspend_state == SUSPEND_READ) {
601                                         as->suspend_state = SUSPEND_ACKTO;
602                                         atomic_dec(&suspend_acks_pending);
603                                 }
604                         }
605                         up_read(&user_list_lock);
606                         mutex_unlock(&state_lock);
607                 }
608
609                 /* let suspend proceed */
610                 if (err >= 0)
611                         return NOTIFY_OK;
612
613                 /* interrupted by signal */
614                 return NOTIFY_BAD;
615
616         case PM_POST_SUSPEND:
617                 /*
618                  * Anyone on the APM queues will think we're still suspended.
619                  * Send a message so everyone knows we're now awake again.
620                  */
621                 queue_event(APM_NORMAL_RESUME);
622
623                 /*
624                  * Finally, wake up anyone who is sleeping on the suspend.
625                  */
626                 mutex_lock(&state_lock);
627                 down_read(&user_list_lock);
628                 list_for_each_entry(as, &apm_user_list, list) {
629                         if (as->suspend_state == SUSPEND_ACKED) {
630                                 /*
631                                  * TODO: maybe grab error code, needs core
632                                  * changes to push the error to the notifier
633                                  * chain (could use the second parameter if
634                                  * implemented)
635                                  */
636                                 as->suspend_result = 0;
637                                 as->suspend_state = SUSPEND_DONE;
638                         }
639                 }
640                 up_read(&user_list_lock);
641                 mutex_unlock(&state_lock);
642
643                 wake_up(&apm_suspend_waitqueue);
644                 return NOTIFY_OK;
645
646         default:
647                 return NOTIFY_DONE;
648         }
649 }
650
651 static struct notifier_block apm_notif_block = {
652         .notifier_call = apm_suspend_notifier,
653 };
654
655 static int __init apm_init(void)
656 {
657         int ret;
658
659         if (apm_disabled) {
660                 printk(KERN_NOTICE "apm: disabled on user request.\n");
661                 return -ENODEV;
662         }
663
664         kapmd_tsk = kthread_create(kapmd, NULL, "kapmd");
665         if (IS_ERR(kapmd_tsk)) {
666                 ret = PTR_ERR(kapmd_tsk);
667                 kapmd_tsk = NULL;
668                 goto out;
669         }
670         wake_up_process(kapmd_tsk);
671
672 #ifdef CONFIG_PROC_FS
673         proc_create("apm", 0, NULL, &apm_proc_fops);
674 #endif
675
676         ret = misc_register(&apm_device);
677         if (ret)
678                 goto out_stop;
679
680         ret = register_pm_notifier(&apm_notif_block);
681         if (ret)
682                 goto out_unregister;
683
684         return 0;
685
686  out_unregister:
687         misc_deregister(&apm_device);
688  out_stop:
689         remove_proc_entry("apm", NULL);
690         kthread_stop(kapmd_tsk);
691  out:
692         return ret;
693 }
694
695 static void __exit apm_exit(void)
696 {
697         unregister_pm_notifier(&apm_notif_block);
698         misc_deregister(&apm_device);
699         remove_proc_entry("apm", NULL);
700
701         kthread_stop(kapmd_tsk);
702 }
703
704 module_init(apm_init);
705 module_exit(apm_exit);
706
707 MODULE_AUTHOR("Stephen Rothwell");
708 MODULE_DESCRIPTION("Advanced Power Management");
709 MODULE_LICENSE("GPL");
710
711 #ifndef MODULE
712 static int __init apm_setup(char *str)
713 {
714         while ((str != NULL) && (*str != '\0')) {
715                 if (strncmp(str, "off", 3) == 0)
716                         apm_disabled = 1;
717                 if (strncmp(str, "on", 2) == 0)
718                         apm_disabled = 0;
719                 str = strchr(str, ',');
720                 if (str != NULL)
721                         str += strspn(str, ", \t");
722         }
723         return 1;
724 }
725
726 __setup("apm=", apm_setup);
727 #endif
728
729 /**
730  * apm_queue_event - queue an APM event for kapmd
731  * @event: APM event
732  *
733  * Queue an APM event for kapmd to process and ultimately take the
734  * appropriate action.  Only a subset of events are handled:
735  *   %APM_LOW_BATTERY
736  *   %APM_POWER_STATUS_CHANGE
737  *   %APM_USER_SUSPEND
738  *   %APM_SYS_SUSPEND
739  *   %APM_CRITICAL_SUSPEND
740  */
741 void apm_queue_event(apm_event_t event)
742 {
743         unsigned long flags;
744
745         spin_lock_irqsave(&kapmd_queue_lock, flags);
746         queue_add_event(&kapmd_queue, event);
747         spin_unlock_irqrestore(&kapmd_queue_lock, flags);
748
749         wake_up_interruptible(&kapmd_wait);
750 }
751 EXPORT_SYMBOL(apm_queue_event);