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kern_pmf.c revision 1.19 
      1 /* $NetBSD: kern_pmf.c,v 1.19 2008/05/05 00:15:57 jmcneill Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2007 Jared D. McNeill <jmcneill (at) 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 1.19 2008/05/05 00:15:57 jmcneill 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/syscallargs.h> /* for sys_sync */
     42 #include <sys/workqueue.h>
     43 #include <prop/proplib.h>
     44 #include <sys/condvar.h>
     45 #include <sys/mutex.h>
     46 #include <sys/proc.h>
     47 #include <sys/reboot.h>	/* for RB_NOSYNC */
     48 #include <sys/sched.h>
     49 
     50 /* XXX ugly special case, but for now the only client */
     51 #include "wsdisplay.h"
     52 #if NWSDISPLAY > 0
     53 #include <dev/wscons/wsdisplayvar.h>
     54 #endif
     55 
     56 #ifdef PMF_DEBUG
     57 int pmf_debug_event;
     58 int pmf_debug_idle;
     59 int pmf_debug_transition;
     60 
     61 #define	PMF_EVENT_PRINTF(x)		if (pmf_debug_event) printf x
     62 #define	PMF_IDLE_PRINTF(x)		if (pmf_debug_idle) printf x
     63 #define	PMF_TRANSITION_PRINTF(x)	if (pmf_debug_transition) printf x
     64 #define	PMF_TRANSITION_PRINTF2(y,x)	if (pmf_debug_transition>y) printf x
     65 #else
     66 #define	PMF_EVENT_PRINTF(x)		do { } while (0)
     67 #define	PMF_IDLE_PRINTF(x)		do { } while (0)
     68 #define	PMF_TRANSITION_PRINTF(x)	do { } while (0)
     69 #define	PMF_TRANSITION_PRINTF2(y,x)	do { } while (0)
     70 #endif
     71 
     72 /* #define PMF_DEBUG */
     73 
     74 MALLOC_DEFINE(M_PMF, "pmf", "device pmf messaging memory");
     75 
     76 static prop_dictionary_t pmf_platform = NULL;
     77 static struct workqueue *pmf_event_workqueue;
     78 
     79 typedef struct pmf_event_handler {
     80 	TAILQ_ENTRY(pmf_event_handler) pmf_link;
     81 	pmf_generic_event_t pmf_event;
     82 	void (*pmf_handler)(device_t);
     83 	device_t pmf_device;
     84 	bool pmf_global;
     85 } pmf_event_handler_t;
     86 
     87 static TAILQ_HEAD(, pmf_event_handler) pmf_all_events =
     88     TAILQ_HEAD_INITIALIZER(pmf_all_events);
     89 
     90 typedef struct pmf_event_workitem {
     91 	struct work		pew_work;
     92 	pmf_generic_event_t	pew_event;
     93 	device_t		pew_device;
     94 } pmf_event_workitem_t;
     95 
     96 struct shutdown_state {
     97 	bool initialized;
     98 	deviter_t di;
     99 };
    100 
    101 static device_t shutdown_first(struct shutdown_state *);
    102 static device_t shutdown_next(struct shutdown_state *);
    103 
    104 static bool pmf_device_resume_locked(device_t PMF_FN_PROTO);
    105 static bool pmf_device_suspend_locked(device_t PMF_FN_PROTO);
    106 
    107 static void
    108 pmf_event_worker(struct work *wk, void *dummy)
    109 {
    110 	pmf_event_workitem_t *pew;
    111 	pmf_event_handler_t *event;
    112 
    113 	pew = (void *)wk;
    114 	KASSERT(wk == &pew->pew_work);
    115 	KASSERT(pew != NULL);
    116 
    117 	TAILQ_FOREACH(event, &pmf_all_events, pmf_link) {
    118 		if (event->pmf_event != pew->pew_event)
    119 			continue;
    120 		if (event->pmf_device == pew->pew_device || event->pmf_global)
    121 			(*event->pmf_handler)(event->pmf_device);
    122 	}
    123 
    124 	free(pew, M_TEMP);
    125 }
    126 
    127 static bool
    128 pmf_check_system_drivers(void)
    129 {
    130 	device_t curdev;
    131 	bool unsupported_devs;
    132 	deviter_t di;
    133 
    134 	unsupported_devs = false;
    135 	for (curdev = deviter_first(&di, 0); curdev != NULL;
    136 	     curdev = deviter_next(&di)) {
    137 		if (device_pmf_is_registered(curdev))
    138 			continue;
    139 		if (!unsupported_devs)
    140 			printf("Devices without power management support:");
    141 		printf(" %s", device_xname(curdev));
    142 		unsupported_devs = true;
    143 	}
    144 	deviter_release(&di);
    145 	if (unsupported_devs) {
    146 		printf("\n");
    147 		return false;
    148 	}
    149 	return true;
    150 }
    151 
    152 bool
    153 pmf_system_bus_resume(PMF_FN_ARGS1)
    154 {
    155 	bool rv;
    156 	device_t curdev;
    157 	deviter_t di;
    158 
    159 	aprint_debug("Powering devices:");
    160 	/* D0 handlers are run in order */
    161 	rv = true;
    162 	for (curdev = deviter_first(&di, DEVITER_F_ROOT_FIRST); curdev != NULL;
    163 	     curdev = deviter_next(&di)) {
    164 		if (!device_pmf_is_registered(curdev))
    165 			continue;
    166 		if (device_is_active(curdev) ||
    167 		    !device_is_enabled(curdev))
    168 			continue;
    169 
    170 		aprint_debug(" %s", device_xname(curdev));
    171 
    172 		if (!device_pmf_bus_resume(curdev PMF_FN_CALL)) {
    173 			rv = false;
    174 			aprint_debug("(failed)");
    175 		}
    176 	}
    177 	deviter_release(&di);
    178 	aprint_debug("\n");
    179 
    180 	return rv;
    181 }
    182 
    183 bool
    184 pmf_system_resume(PMF_FN_ARGS1)
    185 {
    186 	bool rv;
    187 	device_t curdev, parent;
    188 	deviter_t di;
    189 
    190 	if (!pmf_check_system_drivers())
    191 		return false;
    192 
    193 	aprint_debug("Resuming devices:");
    194 	/* D0 handlers are run in order */
    195 	rv = true;
    196 	for (curdev = deviter_first(&di, DEVITER_F_ROOT_FIRST); curdev != NULL;
    197 	     curdev = deviter_next(&di)) {
    198 		if (device_is_active(curdev) ||
    199 		    !device_is_enabled(curdev))
    200 			continue;
    201 		parent = device_parent(curdev);
    202 		if (parent != NULL &&
    203 		    !device_is_active(parent))
    204 			continue;
    205 
    206 		aprint_debug(" %s", device_xname(curdev));
    207 
    208 		if (!pmf_device_resume(curdev PMF_FN_CALL)) {
    209 			rv = false;
    210 			aprint_debug("(failed)");
    211 		}
    212 	}
    213 	deviter_release(&di);
    214 	aprint_debug(".\n");
    215 
    216 	KERNEL_UNLOCK_ONE(0);
    217 #if NWSDISPLAY > 0
    218 	if (rv)
    219 		wsdisplay_handlex(1);
    220 #endif
    221 	return rv;
    222 }
    223 
    224 bool
    225 pmf_system_suspend(PMF_FN_ARGS1)
    226 {
    227 	device_t curdev;
    228 	deviter_t di;
    229 
    230 	if (!pmf_check_system_drivers())
    231 		return false;
    232 #if NWSDISPLAY > 0
    233 	if (wsdisplay_handlex(0))
    234 		return false;
    235 #endif
    236 	KERNEL_LOCK(1, 0);
    237 
    238 	/*
    239 	 * Flush buffers only if the shutdown didn't do so
    240 	 * already and if there was no panic.
    241 	 */
    242 	if (doing_shutdown == 0 && panicstr == NULL) {
    243 		printf("Flushing disk caches: ");
    244 		sys_sync(NULL, NULL, NULL);
    245 		if (buf_syncwait() != 0)
    246 			printf("giving up\n");
    247 		else
    248 			printf("done\n");
    249 	}
    250 
    251 	aprint_debug("Suspending devices:");
    252 
    253 	for (curdev = deviter_first(&di, DEVITER_F_LEAVES_FIRST);
    254 	     curdev != NULL;
    255 	     curdev = deviter_next(&di)) {
    256 		if (!device_is_active(curdev))
    257 			continue;
    258 
    259 		aprint_debug(" %s", device_xname(curdev));
    260 
    261 		/* XXX joerg check return value and abort suspend */
    262 		if (!pmf_device_suspend(curdev PMF_FN_CALL))
    263 			aprint_debug("(failed)");
    264 	}
    265 	deviter_release(&di);
    266 
    267 	aprint_debug(".\n");
    268 
    269 	return true;
    270 }
    271 
    272 static device_t
    273 shutdown_first(struct shutdown_state *s)
    274 {
    275 	if (!s->initialized) {
    276 		deviter_init(&s->di, DEVITER_F_SHUTDOWN|DEVITER_F_LEAVES_FIRST);
    277 		s->initialized = true;
    278 	}
    279 	return shutdown_next(s);
    280 }
    281 
    282 static device_t
    283 shutdown_next(struct shutdown_state *s)
    284 {
    285 	device_t dv;
    286 
    287 	while ((dv = deviter_next(&s->di)) != NULL && !device_is_active(dv))
    288 		;
    289 
    290 	return dv;
    291 }
    292 
    293 void
    294 pmf_system_shutdown(int how)
    295 {
    296 	static struct shutdown_state s;
    297 	device_t curdev;
    298 
    299 	aprint_debug("Shutting down devices:");
    300 
    301 	for (curdev = shutdown_first(&s); curdev != NULL;
    302 	     curdev = shutdown_next(&s)) {
    303 		aprint_debug(" attempting %s shutdown",
    304 		    device_xname(curdev));
    305 		if (!device_pmf_is_registered(curdev))
    306 			aprint_debug("(skipped)");
    307 #if 0 /* needed? */
    308 		else if (!device_pmf_class_shutdown(curdev, how))
    309 			aprint_debug("(failed)");
    310 #endif
    311 		else if (!device_pmf_driver_shutdown(curdev, how))
    312 			aprint_debug("(failed)");
    313 		else if (!device_pmf_bus_shutdown(curdev, how))
    314 			aprint_debug("(failed)");
    315 	}
    316 
    317 	aprint_debug(".\n");
    318 }
    319 
    320 bool
    321 pmf_set_platform(const char *key, const char *value)
    322 {
    323 	if (pmf_platform == NULL)
    324 		pmf_platform = prop_dictionary_create();
    325 	if (pmf_platform == NULL)
    326 		return false;
    327 
    328 	return prop_dictionary_set_cstring(pmf_platform, key, value);
    329 }
    330 
    331 const char *
    332 pmf_get_platform(const char *key)
    333 {
    334 	const char *value;
    335 
    336 	if (pmf_platform == NULL)
    337 		return NULL;
    338 
    339 	if (!prop_dictionary_get_cstring_nocopy(pmf_platform, key, &value))
    340 		return NULL;
    341 
    342 	return value;
    343 }
    344 
    345 bool
    346 pmf_device_register1(device_t dev,
    347     bool (*suspend)(device_t PMF_FN_PROTO),
    348     bool (*resume)(device_t PMF_FN_PROTO),
    349     bool (*shutdown)(device_t, int))
    350 {
    351 	if (!device_pmf_driver_register(dev, suspend, resume, shutdown))
    352 		return false;
    353 
    354 	if (!device_pmf_driver_child_register(dev)) {
    355 		device_pmf_driver_deregister(dev);
    356 		return false;
    357 	}
    358 
    359 	return true;
    360 }
    361 
    362 void
    363 pmf_device_deregister(device_t dev)
    364 {
    365 	device_pmf_class_deregister(dev);
    366 	device_pmf_bus_deregister(dev);
    367 	device_pmf_driver_deregister(dev);
    368 }
    369 
    370 bool
    371 pmf_device_suspend_self(device_t dev)
    372 {
    373 	return pmf_device_suspend(dev, PMF_F_SELF);
    374 }
    375 
    376 bool
    377 pmf_device_suspend(device_t dev PMF_FN_ARGS)
    378 {
    379 	bool rc;
    380 
    381 	PMF_TRANSITION_PRINTF(("%s: suspend enter\n", device_xname(dev)));
    382 	if (!device_pmf_is_registered(dev))
    383 		return false;
    384 
    385 	if (!device_pmf_lock(dev PMF_FN_CALL))
    386 		return false;
    387 
    388 	rc = pmf_device_suspend_locked(dev PMF_FN_CALL);
    389 
    390 	device_pmf_unlock(dev PMF_FN_CALL);
    391 
    392 	PMF_TRANSITION_PRINTF(("%s: suspend exit\n", device_xname(dev)));
    393 	return rc;
    394 }
    395 
    396 static bool
    397 pmf_device_suspend_locked(device_t dev PMF_FN_ARGS)
    398 {
    399 	PMF_TRANSITION_PRINTF2(1, ("%s: self suspend\n", device_xname(dev)));
    400 	device_pmf_self_suspend(dev, flags);
    401 	PMF_TRANSITION_PRINTF2(1, ("%s: class suspend\n", device_xname(dev)));
    402 	if (!device_pmf_class_suspend(dev PMF_FN_CALL))
    403 		return false;
    404 	PMF_TRANSITION_PRINTF2(1, ("%s: driver suspend\n", device_xname(dev)));
    405 	if (!device_pmf_driver_suspend(dev PMF_FN_CALL))
    406 		return false;
    407 	PMF_TRANSITION_PRINTF2(1, ("%s: bus suspend\n", device_xname(dev)));
    408 	if (!device_pmf_bus_suspend(dev PMF_FN_CALL))
    409 		return false;
    410 
    411 	return true;
    412 }
    413 
    414 bool
    415 pmf_device_resume_self(device_t dev)
    416 {
    417 	return pmf_device_resume(dev, PMF_F_SELF);
    418 }
    419 
    420 bool
    421 pmf_device_resume(device_t dev PMF_FN_ARGS)
    422 {
    423 	bool rc;
    424 
    425 	PMF_TRANSITION_PRINTF(("%s: resume enter\n", device_xname(dev)));
    426 	if (!device_pmf_is_registered(dev))
    427 		return false;
    428 
    429 	if (!device_pmf_lock(dev PMF_FN_CALL))
    430 		return false;
    431 
    432 	rc = pmf_device_resume_locked(dev PMF_FN_CALL);
    433 
    434 	device_pmf_unlock(dev PMF_FN_CALL);
    435 
    436 	PMF_TRANSITION_PRINTF(("%s: resume exit\n", device_xname(dev)));
    437 	return rc;
    438 }
    439 
    440 static bool
    441 pmf_device_resume_locked(device_t dev PMF_FN_ARGS)
    442 {
    443 	PMF_TRANSITION_PRINTF2(1, ("%s: bus resume\n", device_xname(dev)));
    444 	if (!device_pmf_bus_resume(dev PMF_FN_CALL))
    445 		return false;
    446 	PMF_TRANSITION_PRINTF2(1, ("%s: driver resume\n", device_xname(dev)));
    447 	if (!device_pmf_driver_resume(dev PMF_FN_CALL))
    448 		return false;
    449 	PMF_TRANSITION_PRINTF2(1, ("%s: class resume\n", device_xname(dev)));
    450 	if (!device_pmf_class_resume(dev PMF_FN_CALL))
    451 		return false;
    452 	PMF_TRANSITION_PRINTF2(1, ("%s: self resume\n", device_xname(dev)));
    453 	device_pmf_self_resume(dev, flags);
    454 
    455 	return true;
    456 }
    457 
    458 bool
    459 pmf_device_recursive_suspend(device_t dv PMF_FN_ARGS)
    460 {
    461 	bool rv = true;
    462 	device_t curdev;
    463 	deviter_t di;
    464 
    465 	if (!device_is_active(dv))
    466 		return true;
    467 
    468 	for (curdev = deviter_first(&di, 0); curdev != NULL;
    469 	     curdev = deviter_next(&di)) {
    470 		if (device_parent(curdev) != dv)
    471 			continue;
    472 		if (!pmf_device_recursive_suspend(curdev PMF_FN_CALL)) {
    473 			rv = false;
    474 			break;
    475 		}
    476 	}
    477 	deviter_release(&di);
    478 
    479 	return rv && pmf_device_suspend(dv PMF_FN_CALL);
    480 }
    481 
    482 bool
    483 pmf_device_recursive_resume(device_t dv PMF_FN_ARGS)
    484 {
    485 	device_t parent;
    486 
    487 	if (device_is_active(dv))
    488 		return true;
    489 
    490 	parent = device_parent(dv);
    491 	if (parent != NULL) {
    492 		if (!pmf_device_recursive_resume(parent PMF_FN_CALL))
    493 			return false;
    494 	}
    495 
    496 	return pmf_device_resume(dv PMF_FN_CALL);
    497 }
    498 
    499 bool
    500 pmf_device_resume_subtree(device_t dv PMF_FN_ARGS)
    501 {
    502 	bool rv = true;
    503 	device_t curdev;
    504 	deviter_t di;
    505 
    506 	if (!pmf_device_recursive_resume(dv PMF_FN_CALL))
    507 		return false;
    508 
    509 	for (curdev = deviter_first(&di, 0); curdev != NULL;
    510 	     curdev = deviter_next(&di)) {
    511 		if (device_parent(curdev) != dv)
    512 			continue;
    513 		if (!pmf_device_resume_subtree(curdev PMF_FN_CALL)) {
    514 			rv = false;
    515 			break;
    516 		}
    517 	}
    518 	deviter_release(&di);
    519 	return rv;
    520 }
    521 
    522 #include <net/if.h>
    523 
    524 static bool
    525 pmf_class_network_suspend(device_t dev PMF_FN_ARGS)
    526 {
    527 	struct ifnet *ifp = device_pmf_class_private(dev);
    528 	int s;
    529 
    530 	s = splnet();
    531 	(*ifp->if_stop)(ifp, 0);
    532 	splx(s);
    533 
    534 	return true;
    535 }
    536 
    537 static bool
    538 pmf_class_network_resume(device_t dev PMF_FN_ARGS)
    539 {
    540 	struct ifnet *ifp = device_pmf_class_private(dev);
    541 	int s;
    542 
    543 	if ((flags & PMF_F_SELF) != 0)
    544 		return true;
    545 
    546 	s = splnet();
    547 	if (ifp->if_flags & IFF_UP) {
    548 		ifp->if_flags &= ~IFF_RUNNING;
    549 		if ((*ifp->if_init)(ifp) != 0)
    550 			aprint_normal_ifnet(ifp, "resume failed\n");
    551 		(*ifp->if_start)(ifp);
    552 	}
    553 	splx(s);
    554 
    555 	return true;
    556 }
    557 
    558 void
    559 pmf_class_network_register(device_t dev, struct ifnet *ifp)
    560 {
    561 	device_pmf_class_register(dev, ifp, pmf_class_network_suspend,
    562 	    pmf_class_network_resume, NULL);
    563 }
    564 
    565 bool
    566 pmf_event_inject(device_t dv, pmf_generic_event_t ev)
    567 {
    568 	pmf_event_workitem_t *pew;
    569 
    570 	pew = malloc(sizeof(pmf_event_workitem_t), M_TEMP, M_NOWAIT);
    571 	if (pew == NULL) {
    572 		PMF_EVENT_PRINTF(("%s: PMF event %d dropped (no memory)\n",
    573 		    dv ? device_xname(dv) : "<anonymous>", ev));
    574 		return false;
    575 	}
    576 
    577 	pew->pew_event = ev;
    578 	pew->pew_device = dv;
    579 
    580 	workqueue_enqueue(pmf_event_workqueue, (void *)pew, NULL);
    581 	PMF_EVENT_PRINTF(("%s: PMF event %d injected\n",
    582 	    dv ? device_xname(dv) : "<anonymous>", ev));
    583 
    584 	return true;
    585 }
    586 
    587 bool
    588 pmf_event_register(device_t dv, pmf_generic_event_t ev,
    589     void (*handler)(device_t), bool global)
    590 {
    591 	pmf_event_handler_t *event;
    592 
    593 	event = malloc(sizeof(*event), M_DEVBUF, M_WAITOK);
    594 	event->pmf_event = ev;
    595 	event->pmf_handler = handler;
    596 	event->pmf_device = dv;
    597 	event->pmf_global = global;
    598 	TAILQ_INSERT_TAIL(&pmf_all_events, event, pmf_link);
    599 
    600 	return true;
    601 }
    602 
    603 void
    604 pmf_event_deregister(device_t dv, pmf_generic_event_t ev,
    605     void (*handler)(device_t), bool global)
    606 {
    607 	pmf_event_handler_t *event;
    608 
    609 	TAILQ_FOREACH(event, &pmf_all_events, pmf_link) {
    610 		if (event->pmf_event != ev)
    611 			continue;
    612 		if (event->pmf_device != dv)
    613 			continue;
    614 		if (event->pmf_global != global)
    615 			continue;
    616 		if (event->pmf_handler != handler)
    617 			continue;
    618 		TAILQ_REMOVE(&pmf_all_events, event, pmf_link);
    619 		free(event, M_DEVBUF);
    620 		return;
    621 	}
    622 }
    623 
    624 struct display_class_softc {
    625 	TAILQ_ENTRY(display_class_softc) dc_link;
    626 	device_t dc_dev;
    627 };
    628 
    629 static TAILQ_HEAD(, display_class_softc) all_displays;
    630 static callout_t global_idle_counter;
    631 static int idle_timeout = 30;
    632 
    633 static void
    634 input_idle(void *dummy)
    635 {
    636 	PMF_IDLE_PRINTF(("Input idle handler called\n"));
    637 	pmf_event_inject(NULL, PMFE_DISPLAY_OFF);
    638 }
    639 
    640 static void
    641 input_activity_handler(device_t dv, devactive_t type)
    642 {
    643 	if (!TAILQ_EMPTY(&all_displays))
    644 		callout_schedule(&global_idle_counter, idle_timeout * hz);
    645 }
    646 
    647 static void
    648 pmf_class_input_deregister(device_t dv)
    649 {
    650 	device_active_deregister(dv, input_activity_handler);
    651 }
    652 
    653 bool
    654 pmf_class_input_register(device_t dv)
    655 {
    656 	if (!device_active_register(dv, input_activity_handler))
    657 		return false;
    658 
    659 	device_pmf_class_register(dv, NULL, NULL, NULL,
    660 	    pmf_class_input_deregister);
    661 
    662 	return true;
    663 }
    664 
    665 static void
    666 pmf_class_display_deregister(device_t dv)
    667 {
    668 	struct display_class_softc *sc = device_pmf_class_private(dv);
    669 	int s;
    670 
    671 	s = splsoftclock();
    672 	TAILQ_REMOVE(&all_displays, sc, dc_link);
    673 	if (TAILQ_EMPTY(&all_displays))
    674 		callout_stop(&global_idle_counter);
    675 	splx(s);
    676 
    677 	free(sc, M_DEVBUF);
    678 }
    679 
    680 bool
    681 pmf_class_display_register(device_t dv)
    682 {
    683 	struct display_class_softc *sc;
    684 	int s;
    685 
    686 	sc = malloc(sizeof(*sc), M_DEVBUF, M_WAITOK);
    687 
    688 	s = splsoftclock();
    689 	if (TAILQ_EMPTY(&all_displays))
    690 		callout_schedule(&global_idle_counter, idle_timeout * hz);
    691 
    692 	TAILQ_INSERT_HEAD(&all_displays, sc, dc_link);
    693 	splx(s);
    694 
    695 	device_pmf_class_register(dv, sc, NULL, NULL,
    696 	    pmf_class_display_deregister);
    697 
    698 	return true;
    699 }
    700 
    701 void
    702 pmf_init(void)
    703 {
    704 	int err;
    705 
    706 	KASSERT(pmf_event_workqueue == NULL);
    707 	err = workqueue_create(&pmf_event_workqueue, "pmfevent",
    708 	    pmf_event_worker, NULL, PRI_NONE, IPL_VM, 0);
    709 	if (err)
    710 		panic("couldn't create pmfevent workqueue");
    711 
    712 	callout_init(&global_idle_counter, 0);
    713 	callout_setfunc(&global_idle_counter, input_idle, NULL);
    714 }
    715