xref: /netbsd-src/sys/kern/kern_pmf.c (revision b5677b36047b601b9addaaa494a58ceae82c2a6c)
1 /* $NetBSD: kern_pmf.c,v 1.24 2009/04/07 18:16:28 dyoung Exp $ */
2 
3 /*-
4  * Copyright (c) 2007 Jared D. McNeill <jmcneill@invisible.ca>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
17  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
18  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
19  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
20  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26  * POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __KERNEL_RCSID(0, "$NetBSD: kern_pmf.c,v 1.24 2009/04/07 18:16:28 dyoung Exp $");
31 
32 #include <sys/types.h>
33 #include <sys/param.h>
34 #include <sys/malloc.h>
35 #include <sys/buf.h>
36 #include <sys/callout.h>
37 #include <sys/kernel.h>
38 #include <sys/device.h>
39 #include <sys/pmf.h>
40 #include <sys/queue.h>
41 #include <sys/sched.h>
42 #include <sys/syscallargs.h> /* for sys_sync */
43 #include <sys/workqueue.h>
44 #include <prop/proplib.h>
45 #include <sys/condvar.h>
46 #include <sys/mutex.h>
47 #include <sys/proc.h>
48 #include <sys/reboot.h>	/* for RB_NOSYNC */
49 #include <sys/sched.h>
50 
51 /* XXX ugly special case, but for now the only client */
52 #include "wsdisplay.h"
53 #if NWSDISPLAY > 0
54 #include <dev/wscons/wsdisplayvar.h>
55 #endif
56 
57 #ifdef PMF_DEBUG
58 int pmf_debug_event;
59 int pmf_debug_idle;
60 int pmf_debug_transition;
61 
62 #define	PMF_EVENT_PRINTF(x)		if (pmf_debug_event) printf x
63 #define	PMF_IDLE_PRINTF(x)		if (pmf_debug_idle) printf x
64 #define	PMF_TRANSITION_PRINTF(x)	if (pmf_debug_transition) printf x
65 #define	PMF_TRANSITION_PRINTF2(y,x)	if (pmf_debug_transition>y) printf x
66 #else
67 #define	PMF_EVENT_PRINTF(x)		do { } while (0)
68 #define	PMF_IDLE_PRINTF(x)		do { } while (0)
69 #define	PMF_TRANSITION_PRINTF(x)	do { } while (0)
70 #define	PMF_TRANSITION_PRINTF2(y,x)	do { } while (0)
71 #endif
72 
73 /* #define PMF_DEBUG */
74 
75 MALLOC_DEFINE(M_PMF, "pmf", "device pmf messaging memory");
76 
77 static prop_dictionary_t pmf_platform = NULL;
78 static struct workqueue *pmf_event_workqueue;
79 
80 typedef struct pmf_event_handler {
81 	TAILQ_ENTRY(pmf_event_handler) pmf_link;
82 	pmf_generic_event_t pmf_event;
83 	void (*pmf_handler)(device_t);
84 	device_t pmf_device;
85 	bool pmf_global;
86 } pmf_event_handler_t;
87 
88 static TAILQ_HEAD(, pmf_event_handler) pmf_all_events =
89     TAILQ_HEAD_INITIALIZER(pmf_all_events);
90 
91 typedef struct pmf_event_workitem {
92 	struct work		pew_work;
93 	pmf_generic_event_t	pew_event;
94 	device_t		pew_device;
95 } pmf_event_workitem_t;
96 
97 struct shutdown_state {
98 	bool initialized;
99 	deviter_t di;
100 };
101 
102 static device_t shutdown_first(struct shutdown_state *);
103 static device_t shutdown_next(struct shutdown_state *);
104 
105 static bool pmf_device_resume_locked(device_t PMF_FN_PROTO);
106 static bool pmf_device_suspend_locked(device_t PMF_FN_PROTO);
107 
108 static void
109 pmf_event_worker(struct work *wk, void *dummy)
110 {
111 	pmf_event_workitem_t *pew;
112 	pmf_event_handler_t *event;
113 
114 	pew = (void *)wk;
115 	KASSERT(wk == &pew->pew_work);
116 	KASSERT(pew != NULL);
117 
118 	TAILQ_FOREACH(event, &pmf_all_events, pmf_link) {
119 		if (event->pmf_event != pew->pew_event)
120 			continue;
121 		if (event->pmf_device == pew->pew_device || event->pmf_global)
122 			(*event->pmf_handler)(event->pmf_device);
123 	}
124 
125 	free(pew, M_TEMP);
126 }
127 
128 static bool
129 pmf_check_system_drivers(void)
130 {
131 	device_t curdev;
132 	bool unsupported_devs;
133 	deviter_t di;
134 
135 	unsupported_devs = false;
136 	for (curdev = deviter_first(&di, 0); curdev != NULL;
137 	     curdev = deviter_next(&di)) {
138 		if (device_pmf_is_registered(curdev))
139 			continue;
140 		if (!unsupported_devs)
141 			printf("Devices without power management support:");
142 		printf(" %s", device_xname(curdev));
143 		unsupported_devs = true;
144 	}
145 	deviter_release(&di);
146 	if (unsupported_devs) {
147 		printf("\n");
148 		return false;
149 	}
150 	return true;
151 }
152 
153 bool
154 pmf_system_bus_resume(PMF_FN_ARGS1)
155 {
156 	bool rv;
157 	device_t curdev;
158 	deviter_t di;
159 
160 	aprint_debug("Powering devices:");
161 	/* D0 handlers are run in order */
162 	rv = true;
163 	for (curdev = deviter_first(&di, DEVITER_F_ROOT_FIRST); curdev != NULL;
164 	     curdev = deviter_next(&di)) {
165 		if (!device_pmf_is_registered(curdev))
166 			continue;
167 		if (device_is_active(curdev) ||
168 		    !device_is_enabled(curdev))
169 			continue;
170 
171 		aprint_debug(" %s", device_xname(curdev));
172 
173 		if (!device_pmf_bus_resume(curdev PMF_FN_CALL)) {
174 			rv = false;
175 			aprint_debug("(failed)");
176 		}
177 	}
178 	deviter_release(&di);
179 	aprint_debug("\n");
180 
181 	return rv;
182 }
183 
184 bool
185 pmf_system_resume(PMF_FN_ARGS1)
186 {
187 	bool rv;
188 	device_t curdev, parent;
189 	deviter_t di;
190 
191 	if (!pmf_check_system_drivers())
192 		return false;
193 
194 	aprint_debug("Resuming devices:");
195 	/* D0 handlers are run in order */
196 	rv = true;
197 	for (curdev = deviter_first(&di, DEVITER_F_ROOT_FIRST); curdev != NULL;
198 	     curdev = deviter_next(&di)) {
199 		if (device_is_active(curdev) ||
200 		    !device_is_enabled(curdev))
201 			continue;
202 		parent = device_parent(curdev);
203 		if (parent != NULL &&
204 		    !device_is_active(parent))
205 			continue;
206 
207 		aprint_debug(" %s", device_xname(curdev));
208 
209 		if (!pmf_device_resume(curdev PMF_FN_CALL)) {
210 			rv = false;
211 			aprint_debug("(failed)");
212 		}
213 	}
214 	deviter_release(&di);
215 	aprint_debug(".\n");
216 
217 	KERNEL_UNLOCK_ONE(0);
218 #if NWSDISPLAY > 0
219 	if (rv)
220 		wsdisplay_handlex(1);
221 #endif
222 	return rv;
223 }
224 
225 bool
226 pmf_system_suspend(PMF_FN_ARGS1)
227 {
228 	device_t curdev;
229 	deviter_t di;
230 
231 	if (!pmf_check_system_drivers())
232 		return false;
233 #if NWSDISPLAY > 0
234 	if (wsdisplay_handlex(0))
235 		return false;
236 #endif
237 	KERNEL_LOCK(1, 0);
238 
239 	/*
240 	 * Flush buffers only if the shutdown didn't do so
241 	 * already and if there was no panic.
242 	 */
243 	if (doing_shutdown == 0 && panicstr == NULL) {
244 		printf("Flushing disk caches: ");
245 		sys_sync(NULL, NULL, NULL);
246 		if (buf_syncwait() != 0)
247 			printf("giving up\n");
248 		else
249 			printf("done\n");
250 	}
251 
252 	aprint_debug("Suspending devices:");
253 
254 	for (curdev = deviter_first(&di, DEVITER_F_LEAVES_FIRST);
255 	     curdev != NULL;
256 	     curdev = deviter_next(&di)) {
257 		if (!device_is_active(curdev))
258 			continue;
259 
260 		aprint_debug(" %s", device_xname(curdev));
261 
262 		/* XXX joerg check return value and abort suspend */
263 		if (!pmf_device_suspend(curdev PMF_FN_CALL))
264 			aprint_debug("(failed)");
265 	}
266 	deviter_release(&di);
267 
268 	aprint_debug(".\n");
269 
270 	return true;
271 }
272 
273 static device_t
274 shutdown_first(struct shutdown_state *s)
275 {
276 	if (!s->initialized) {
277 		deviter_init(&s->di, DEVITER_F_SHUTDOWN|DEVITER_F_LEAVES_FIRST);
278 		s->initialized = true;
279 	}
280 	return shutdown_next(s);
281 }
282 
283 static device_t
284 shutdown_next(struct shutdown_state *s)
285 {
286 	device_t dv;
287 
288 	while ((dv = deviter_next(&s->di)) != NULL && !device_is_active(dv))
289 		;
290 
291 	return dv;
292 }
293 
294 void
295 pmf_system_shutdown(int how)
296 {
297 	static struct shutdown_state s;
298 	device_t curdev;
299 
300 	aprint_debug("Shutting down devices:");
301 	suspendsched();
302 
303 	for (curdev = shutdown_first(&s); curdev != NULL;
304 	     curdev = shutdown_next(&s)) {
305 		aprint_debug(" attempting %s shutdown", device_xname(curdev));
306 		if ((boothowto & RB_NOSYNC) == 0 &&
307 		    config_detach(curdev, DETACH_SHUTDOWN) == 0)
308 			aprint_debug("(detached)");
309 		else if (!device_pmf_is_registered(curdev))
310 			aprint_debug("(skipped)");
311 #if 0 /* needed? */
312 		else if (!device_pmf_class_shutdown(curdev, how))
313 			aprint_debug("(failed)");
314 #endif
315 		else if (!device_pmf_driver_shutdown(curdev, how))
316 			aprint_debug("(failed)");
317 		else if (!device_pmf_bus_shutdown(curdev, how))
318 			aprint_debug("(failed)");
319 	}
320 
321 	aprint_debug(".\n");
322 }
323 
324 bool
325 pmf_set_platform(const char *key, const char *value)
326 {
327 	if (pmf_platform == NULL)
328 		pmf_platform = prop_dictionary_create();
329 	if (pmf_platform == NULL)
330 		return false;
331 
332 	return prop_dictionary_set_cstring(pmf_platform, key, value);
333 }
334 
335 const char *
336 pmf_get_platform(const char *key)
337 {
338 	const char *value;
339 
340 	if (pmf_platform == NULL)
341 		return NULL;
342 
343 	if (!prop_dictionary_get_cstring_nocopy(pmf_platform, key, &value))
344 		return NULL;
345 
346 	return value;
347 }
348 
349 bool
350 pmf_device_register1(device_t dev,
351     bool (*suspend)(device_t PMF_FN_PROTO),
352     bool (*resume)(device_t PMF_FN_PROTO),
353     bool (*shutdown)(device_t, int))
354 {
355 	if (!device_pmf_driver_register(dev, suspend, resume, shutdown))
356 		return false;
357 
358 	if (!device_pmf_driver_child_register(dev)) {
359 		device_pmf_driver_deregister(dev);
360 		return false;
361 	}
362 
363 	return true;
364 }
365 
366 void
367 pmf_device_deregister(device_t dev)
368 {
369 	device_pmf_class_deregister(dev);
370 	device_pmf_bus_deregister(dev);
371 	device_pmf_driver_deregister(dev);
372 }
373 
374 bool
375 pmf_device_suspend_self(device_t dev)
376 {
377 	return pmf_device_suspend(dev, PMF_F_SELF);
378 }
379 
380 bool
381 pmf_device_suspend(device_t dev PMF_FN_ARGS)
382 {
383 	bool rc;
384 
385 	PMF_TRANSITION_PRINTF(("%s: suspend enter\n", device_xname(dev)));
386 	if (!device_pmf_is_registered(dev))
387 		return false;
388 
389 	if (!device_pmf_lock(dev PMF_FN_CALL))
390 		return false;
391 
392 	rc = pmf_device_suspend_locked(dev PMF_FN_CALL);
393 
394 	device_pmf_unlock(dev PMF_FN_CALL);
395 
396 	PMF_TRANSITION_PRINTF(("%s: suspend exit\n", device_xname(dev)));
397 	return rc;
398 }
399 
400 static bool
401 pmf_device_suspend_locked(device_t dev PMF_FN_ARGS)
402 {
403 	PMF_TRANSITION_PRINTF2(1, ("%s: self suspend\n", device_xname(dev)));
404 	device_pmf_self_suspend(dev, flags);
405 	PMF_TRANSITION_PRINTF2(1, ("%s: class suspend\n", device_xname(dev)));
406 	if (!device_pmf_class_suspend(dev PMF_FN_CALL))
407 		return false;
408 	PMF_TRANSITION_PRINTF2(1, ("%s: driver suspend\n", device_xname(dev)));
409 	if (!device_pmf_driver_suspend(dev PMF_FN_CALL))
410 		return false;
411 	PMF_TRANSITION_PRINTF2(1, ("%s: bus suspend\n", device_xname(dev)));
412 	if (!device_pmf_bus_suspend(dev PMF_FN_CALL))
413 		return false;
414 
415 	return true;
416 }
417 
418 bool
419 pmf_device_resume_self(device_t dev)
420 {
421 	return pmf_device_resume(dev, PMF_F_SELF);
422 }
423 
424 bool
425 pmf_device_resume(device_t dev PMF_FN_ARGS)
426 {
427 	bool rc;
428 
429 	PMF_TRANSITION_PRINTF(("%s: resume enter\n", device_xname(dev)));
430 	if (!device_pmf_is_registered(dev))
431 		return false;
432 
433 	if (!device_pmf_lock(dev PMF_FN_CALL))
434 		return false;
435 
436 	rc = pmf_device_resume_locked(dev PMF_FN_CALL);
437 
438 	device_pmf_unlock(dev PMF_FN_CALL);
439 
440 	PMF_TRANSITION_PRINTF(("%s: resume exit\n", device_xname(dev)));
441 	return rc;
442 }
443 
444 static bool
445 pmf_device_resume_locked(device_t dev PMF_FN_ARGS)
446 {
447 	PMF_TRANSITION_PRINTF2(1, ("%s: bus resume\n", device_xname(dev)));
448 	if (!device_pmf_bus_resume(dev PMF_FN_CALL))
449 		return false;
450 	PMF_TRANSITION_PRINTF2(1, ("%s: driver resume\n", device_xname(dev)));
451 	if (!device_pmf_driver_resume(dev PMF_FN_CALL))
452 		return false;
453 	PMF_TRANSITION_PRINTF2(1, ("%s: class resume\n", device_xname(dev)));
454 	if (!device_pmf_class_resume(dev PMF_FN_CALL))
455 		return false;
456 	PMF_TRANSITION_PRINTF2(1, ("%s: self resume\n", device_xname(dev)));
457 	device_pmf_self_resume(dev, flags);
458 
459 	return true;
460 }
461 
462 bool
463 pmf_device_recursive_suspend(device_t dv PMF_FN_ARGS)
464 {
465 	bool rv = true;
466 	device_t curdev;
467 	deviter_t di;
468 
469 	if (!device_is_active(dv))
470 		return true;
471 
472 	for (curdev = deviter_first(&di, 0); curdev != NULL;
473 	     curdev = deviter_next(&di)) {
474 		if (device_parent(curdev) != dv)
475 			continue;
476 		if (!pmf_device_recursive_suspend(curdev PMF_FN_CALL)) {
477 			rv = false;
478 			break;
479 		}
480 	}
481 	deviter_release(&di);
482 
483 	return rv && pmf_device_suspend(dv PMF_FN_CALL);
484 }
485 
486 bool
487 pmf_device_recursive_resume(device_t dv PMF_FN_ARGS)
488 {
489 	device_t parent;
490 
491 	if (device_is_active(dv))
492 		return true;
493 
494 	parent = device_parent(dv);
495 	if (parent != NULL) {
496 		if (!pmf_device_recursive_resume(parent PMF_FN_CALL))
497 			return false;
498 	}
499 
500 	return pmf_device_resume(dv PMF_FN_CALL);
501 }
502 
503 bool
504 pmf_device_resume_descendants(device_t dv PMF_FN_ARGS)
505 {
506 	bool rv = true;
507 	device_t curdev;
508 	deviter_t di;
509 
510 	for (curdev = deviter_first(&di, 0); curdev != NULL;
511 	     curdev = deviter_next(&di)) {
512 		if (device_parent(curdev) != dv)
513 			continue;
514 		if (!pmf_device_resume_subtree(curdev PMF_FN_CALL)) {
515 			rv = false;
516 			break;
517 		}
518 	}
519 	deviter_release(&di);
520 	return rv;
521 }
522 
523 bool
524 pmf_device_resume_subtree(device_t dv PMF_FN_ARGS)
525 {
526 	if (!pmf_device_recursive_resume(dv PMF_FN_CALL))
527 		return false;
528 
529 	return pmf_device_resume_descendants(dv PMF_FN_CALL);
530 }
531 
532 #include <net/if.h>
533 
534 static bool
535 pmf_class_network_suspend(device_t dev PMF_FN_ARGS)
536 {
537 	struct ifnet *ifp = device_pmf_class_private(dev);
538 	int s;
539 
540 	s = splnet();
541 	(*ifp->if_stop)(ifp, 0);
542 	splx(s);
543 
544 	return true;
545 }
546 
547 static bool
548 pmf_class_network_resume(device_t dev PMF_FN_ARGS)
549 {
550 	struct ifnet *ifp = device_pmf_class_private(dev);
551 	int s;
552 
553 	if ((flags & PMF_F_SELF) != 0)
554 		return true;
555 
556 	s = splnet();
557 	if (ifp->if_flags & IFF_UP) {
558 		ifp->if_flags &= ~IFF_RUNNING;
559 		if ((*ifp->if_init)(ifp) != 0)
560 			aprint_normal_ifnet(ifp, "resume failed\n");
561 		(*ifp->if_start)(ifp);
562 	}
563 	splx(s);
564 
565 	return true;
566 }
567 
568 void
569 pmf_class_network_register(device_t dev, struct ifnet *ifp)
570 {
571 	device_pmf_class_register(dev, ifp, pmf_class_network_suspend,
572 	    pmf_class_network_resume, NULL);
573 }
574 
575 bool
576 pmf_event_inject(device_t dv, pmf_generic_event_t ev)
577 {
578 	pmf_event_workitem_t *pew;
579 
580 	pew = malloc(sizeof(pmf_event_workitem_t), M_TEMP, M_NOWAIT);
581 	if (pew == NULL) {
582 		PMF_EVENT_PRINTF(("%s: PMF event %d dropped (no memory)\n",
583 		    dv ? device_xname(dv) : "<anonymous>", ev));
584 		return false;
585 	}
586 
587 	pew->pew_event = ev;
588 	pew->pew_device = dv;
589 
590 	workqueue_enqueue(pmf_event_workqueue, (void *)pew, NULL);
591 	PMF_EVENT_PRINTF(("%s: PMF event %d injected\n",
592 	    dv ? device_xname(dv) : "<anonymous>", ev));
593 
594 	return true;
595 }
596 
597 bool
598 pmf_event_register(device_t dv, pmf_generic_event_t ev,
599     void (*handler)(device_t), bool global)
600 {
601 	pmf_event_handler_t *event;
602 
603 	event = malloc(sizeof(*event), M_DEVBUF, M_WAITOK);
604 	event->pmf_event = ev;
605 	event->pmf_handler = handler;
606 	event->pmf_device = dv;
607 	event->pmf_global = global;
608 	TAILQ_INSERT_TAIL(&pmf_all_events, event, pmf_link);
609 
610 	return true;
611 }
612 
613 void
614 pmf_event_deregister(device_t dv, pmf_generic_event_t ev,
615     void (*handler)(device_t), bool global)
616 {
617 	pmf_event_handler_t *event;
618 
619 	TAILQ_FOREACH(event, &pmf_all_events, pmf_link) {
620 		if (event->pmf_event != ev)
621 			continue;
622 		if (event->pmf_device != dv)
623 			continue;
624 		if (event->pmf_global != global)
625 			continue;
626 		if (event->pmf_handler != handler)
627 			continue;
628 		TAILQ_REMOVE(&pmf_all_events, event, pmf_link);
629 		free(event, M_DEVBUF);
630 		return;
631 	}
632 }
633 
634 struct display_class_softc {
635 	TAILQ_ENTRY(display_class_softc) dc_link;
636 	device_t dc_dev;
637 };
638 
639 static TAILQ_HEAD(, display_class_softc) all_displays;
640 static callout_t global_idle_counter;
641 static int idle_timeout = 30;
642 
643 static void
644 input_idle(void *dummy)
645 {
646 	PMF_IDLE_PRINTF(("Input idle handler called\n"));
647 	pmf_event_inject(NULL, PMFE_DISPLAY_OFF);
648 }
649 
650 static void
651 input_activity_handler(device_t dv, devactive_t type)
652 {
653 	if (!TAILQ_EMPTY(&all_displays))
654 		callout_schedule(&global_idle_counter, idle_timeout * hz);
655 }
656 
657 static void
658 pmf_class_input_deregister(device_t dv)
659 {
660 	device_active_deregister(dv, input_activity_handler);
661 }
662 
663 bool
664 pmf_class_input_register(device_t dv)
665 {
666 	if (!device_active_register(dv, input_activity_handler))
667 		return false;
668 
669 	device_pmf_class_register(dv, NULL, NULL, NULL,
670 	    pmf_class_input_deregister);
671 
672 	return true;
673 }
674 
675 static void
676 pmf_class_display_deregister(device_t dv)
677 {
678 	struct display_class_softc *sc = device_pmf_class_private(dv);
679 	int s;
680 
681 	s = splsoftclock();
682 	TAILQ_REMOVE(&all_displays, sc, dc_link);
683 	if (TAILQ_EMPTY(&all_displays))
684 		callout_stop(&global_idle_counter);
685 	splx(s);
686 
687 	free(sc, M_DEVBUF);
688 }
689 
690 bool
691 pmf_class_display_register(device_t dv)
692 {
693 	struct display_class_softc *sc;
694 	int s;
695 
696 	sc = malloc(sizeof(*sc), M_DEVBUF, M_WAITOK);
697 
698 	s = splsoftclock();
699 	if (TAILQ_EMPTY(&all_displays))
700 		callout_schedule(&global_idle_counter, idle_timeout * hz);
701 
702 	TAILQ_INSERT_HEAD(&all_displays, sc, dc_link);
703 	splx(s);
704 
705 	device_pmf_class_register(dv, sc, NULL, NULL,
706 	    pmf_class_display_deregister);
707 
708 	return true;
709 }
710 
711 void
712 pmf_init(void)
713 {
714 	int err;
715 
716 	KASSERT(pmf_event_workqueue == NULL);
717 	err = workqueue_create(&pmf_event_workqueue, "pmfevent",
718 	    pmf_event_worker, NULL, PRI_NONE, IPL_VM, 0);
719 	if (err)
720 		panic("couldn't create pmfevent workqueue");
721 
722 	callout_init(&global_idle_counter, 0);
723 	callout_setfunc(&global_idle_counter, input_idle, NULL);
724 }
725