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kern_pmf.c revision 1.28 
      1 /* $NetBSD: kern_pmf.c,v 1.28 2009/07/08 18:53:36 dyoung 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 1.28 2009/07/08 18:53:36 dyoung Exp $");
     31 
     32 #include <sys/types.h>
     33 #include <sys/param.h>
     34 #include <sys/kmem.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 static pool_cache_t pew_pc;
     98 
     99 static pmf_event_workitem_t *pmf_event_workitem_get(void);
    100 static void pmf_event_workitem_put(pmf_event_workitem_t *);
    101 
    102 
    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 	pmf_event_workitem_put(pew);
    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, NULL);
    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 bool
    273 shutdown_all(int how)
    274 {
    275 	static struct shutdown_state s;
    276 	device_t curdev;
    277 	bool progress = false;
    278 
    279 	for (curdev = shutdown_first(&s); curdev != NULL;
    280 	     curdev = shutdown_next(&s)) {
    281 		aprint_debug(" shutting down %s, ", device_xname(curdev));
    282 		if (!device_pmf_is_registered(curdev))
    283 			aprint_debug("skipped.");
    284 #if 0 /* needed? */
    285 		else if (!device_pmf_class_shutdown(curdev, how))
    286 			aprint_debug("failed.");
    287 #endif
    288 		else if (!device_pmf_driver_shutdown(curdev, how))
    289 			aprint_debug("failed.");
    290 		else if (!device_pmf_bus_shutdown(curdev, how))
    291 			aprint_debug("failed.");
    292 		else {
    293 			progress = true;
    294 			aprint_debug("success.");
    295 		}
    296 	}
    297 	return progress;
    298 }
    299 
    300 void
    301 pmf_system_shutdown(int how)
    302 {
    303 	aprint_debug("Shutting down devices:");
    304 	shutdown_all(how);
    305 }
    306 
    307 bool
    308 pmf_set_platform(const char *key, const char *value)
    309 {
    310 	if (pmf_platform == NULL)
    311 		pmf_platform = prop_dictionary_create();
    312 	if (pmf_platform == NULL)
    313 		return false;
    314 
    315 	return prop_dictionary_set_cstring(pmf_platform, key, value);
    316 }
    317 
    318 const char *
    319 pmf_get_platform(const char *key)
    320 {
    321 	const char *value;
    322 
    323 	if (pmf_platform == NULL)
    324 		return NULL;
    325 
    326 	if (!prop_dictionary_get_cstring_nocopy(pmf_platform, key, &value))
    327 		return NULL;
    328 
    329 	return value;
    330 }
    331 
    332 bool
    333 pmf_device_register1(device_t dev,
    334     bool (*suspend)(device_t PMF_FN_PROTO),
    335     bool (*resume)(device_t PMF_FN_PROTO),
    336     bool (*shutdown)(device_t, int))
    337 {
    338 	if (!device_pmf_driver_register(dev, suspend, resume, shutdown))
    339 		return false;
    340 
    341 	if (!device_pmf_driver_child_register(dev)) {
    342 		device_pmf_driver_deregister(dev);
    343 		return false;
    344 	}
    345 
    346 	return true;
    347 }
    348 
    349 void
    350 pmf_device_deregister(device_t dev)
    351 {
    352 	device_pmf_class_deregister(dev);
    353 	device_pmf_bus_deregister(dev);
    354 	device_pmf_driver_deregister(dev);
    355 }
    356 
    357 bool
    358 pmf_device_suspend_self(device_t dev)
    359 {
    360 	return pmf_device_suspend(dev, PMF_F_SELF);
    361 }
    362 
    363 bool
    364 pmf_device_suspend(device_t dev PMF_FN_ARGS)
    365 {
    366 	bool rc;
    367 
    368 	PMF_TRANSITION_PRINTF(("%s: suspend enter\n", device_xname(dev)));
    369 	if (!device_pmf_is_registered(dev))
    370 		return false;
    371 
    372 	if (!device_pmf_lock(dev PMF_FN_CALL))
    373 		return false;
    374 
    375 	rc = pmf_device_suspend_locked(dev PMF_FN_CALL);
    376 
    377 	device_pmf_unlock(dev PMF_FN_CALL);
    378 
    379 	PMF_TRANSITION_PRINTF(("%s: suspend exit\n", device_xname(dev)));
    380 	return rc;
    381 }
    382 
    383 static bool
    384 pmf_device_suspend_locked(device_t dev PMF_FN_ARGS)
    385 {
    386 	PMF_TRANSITION_PRINTF2(1, ("%s: self suspend\n", device_xname(dev)));
    387 	device_pmf_self_suspend(dev, flags);
    388 	PMF_TRANSITION_PRINTF2(1, ("%s: class suspend\n", device_xname(dev)));
    389 	if (!device_pmf_class_suspend(dev PMF_FN_CALL))
    390 		return false;
    391 	PMF_TRANSITION_PRINTF2(1, ("%s: driver suspend\n", device_xname(dev)));
    392 	if (!device_pmf_driver_suspend(dev PMF_FN_CALL))
    393 		return false;
    394 	PMF_TRANSITION_PRINTF2(1, ("%s: bus suspend\n", device_xname(dev)));
    395 	if (!device_pmf_bus_suspend(dev PMF_FN_CALL))
    396 		return false;
    397 
    398 	return true;
    399 }
    400 
    401 bool
    402 pmf_device_resume_self(device_t dev)
    403 {
    404 	return pmf_device_resume(dev, PMF_F_SELF);
    405 }
    406 
    407 bool
    408 pmf_device_resume(device_t dev PMF_FN_ARGS)
    409 {
    410 	bool rc;
    411 
    412 	PMF_TRANSITION_PRINTF(("%s: resume enter\n", device_xname(dev)));
    413 	if (!device_pmf_is_registered(dev))
    414 		return false;
    415 
    416 	if (!device_pmf_lock(dev PMF_FN_CALL))
    417 		return false;
    418 
    419 	rc = pmf_device_resume_locked(dev PMF_FN_CALL);
    420 
    421 	device_pmf_unlock(dev PMF_FN_CALL);
    422 
    423 	PMF_TRANSITION_PRINTF(("%s: resume exit\n", device_xname(dev)));
    424 	return rc;
    425 }
    426 
    427 static bool
    428 pmf_device_resume_locked(device_t dev PMF_FN_ARGS)
    429 {
    430 	PMF_TRANSITION_PRINTF2(1, ("%s: bus resume\n", device_xname(dev)));
    431 	if (!device_pmf_bus_resume(dev PMF_FN_CALL))
    432 		return false;
    433 	PMF_TRANSITION_PRINTF2(1, ("%s: driver resume\n", device_xname(dev)));
    434 	if (!device_pmf_driver_resume(dev PMF_FN_CALL))
    435 		return false;
    436 	PMF_TRANSITION_PRINTF2(1, ("%s: class resume\n", device_xname(dev)));
    437 	if (!device_pmf_class_resume(dev PMF_FN_CALL))
    438 		return false;
    439 	PMF_TRANSITION_PRINTF2(1, ("%s: self resume\n", device_xname(dev)));
    440 	device_pmf_self_resume(dev, flags);
    441 
    442 	return true;
    443 }
    444 
    445 bool
    446 pmf_device_recursive_suspend(device_t dv PMF_FN_ARGS)
    447 {
    448 	bool rv = true;
    449 	device_t curdev;
    450 	deviter_t di;
    451 
    452 	if (!device_is_active(dv))
    453 		return true;
    454 
    455 	for (curdev = deviter_first(&di, 0); curdev != NULL;
    456 	     curdev = deviter_next(&di)) {
    457 		if (device_parent(curdev) != dv)
    458 			continue;
    459 		if (!pmf_device_recursive_suspend(curdev PMF_FN_CALL)) {
    460 			rv = false;
    461 			break;
    462 		}
    463 	}
    464 	deviter_release(&di);
    465 
    466 	return rv && pmf_device_suspend(dv PMF_FN_CALL);
    467 }
    468 
    469 bool
    470 pmf_device_recursive_resume(device_t dv PMF_FN_ARGS)
    471 {
    472 	device_t parent;
    473 
    474 	if (device_is_active(dv))
    475 		return true;
    476 
    477 	parent = device_parent(dv);
    478 	if (parent != NULL) {
    479 		if (!pmf_device_recursive_resume(parent PMF_FN_CALL))
    480 			return false;
    481 	}
    482 
    483 	return pmf_device_resume(dv PMF_FN_CALL);
    484 }
    485 
    486 bool
    487 pmf_device_resume_descendants(device_t dv PMF_FN_ARGS)
    488 {
    489 	bool rv = true;
    490 	device_t curdev;
    491 	deviter_t di;
    492 
    493 	for (curdev = deviter_first(&di, 0); curdev != NULL;
    494 	     curdev = deviter_next(&di)) {
    495 		if (device_parent(curdev) != dv)
    496 			continue;
    497 		if (!pmf_device_resume_subtree(curdev PMF_FN_CALL)) {
    498 			rv = false;
    499 			break;
    500 		}
    501 	}
    502 	deviter_release(&di);
    503 	return rv;
    504 }
    505 
    506 bool
    507 pmf_device_resume_subtree(device_t dv PMF_FN_ARGS)
    508 {
    509 	if (!pmf_device_recursive_resume(dv PMF_FN_CALL))
    510 		return false;
    511 
    512 	return pmf_device_resume_descendants(dv PMF_FN_CALL);
    513 }
    514 
    515 #include <net/if.h>
    516 
    517 static bool
    518 pmf_class_network_suspend(device_t dev PMF_FN_ARGS)
    519 {
    520 	struct ifnet *ifp = device_pmf_class_private(dev);
    521 	int s;
    522 
    523 	s = splnet();
    524 	(*ifp->if_stop)(ifp, 0);
    525 	splx(s);
    526 
    527 	return true;
    528 }
    529 
    530 static bool
    531 pmf_class_network_resume(device_t dev PMF_FN_ARGS)
    532 {
    533 	struct ifnet *ifp = device_pmf_class_private(dev);
    534 	int s;
    535 
    536 	if ((flags & PMF_F_SELF) != 0)
    537 		return true;
    538 
    539 	s = splnet();
    540 	if (ifp->if_flags & IFF_UP) {
    541 		ifp->if_flags &= ~IFF_RUNNING;
    542 		if ((*ifp->if_init)(ifp) != 0)
    543 			aprint_normal_ifnet(ifp, "resume failed\n");
    544 		(*ifp->if_start)(ifp);
    545 	}
    546 	splx(s);
    547 
    548 	return true;
    549 }
    550 
    551 void
    552 pmf_class_network_register(device_t dev, struct ifnet *ifp)
    553 {
    554 	device_pmf_class_register(dev, ifp, pmf_class_network_suspend,
    555 	    pmf_class_network_resume, NULL);
    556 }
    557 
    558 bool
    559 pmf_event_inject(device_t dv, pmf_generic_event_t ev)
    560 {
    561 	pmf_event_workitem_t *pew;
    562 
    563 	pew = pmf_event_workitem_get();
    564 	if (pew == NULL) {
    565 		PMF_EVENT_PRINTF(("%s: PMF event %d dropped (no memory)\n",
    566 		    dv ? device_xname(dv) : "<anonymous>", ev));
    567 		return false;
    568 	}
    569 
    570 	pew->pew_event = ev;
    571 	pew->pew_device = dv;
    572 
    573 	workqueue_enqueue(pmf_event_workqueue, &pew->pew_work, NULL);
    574 	PMF_EVENT_PRINTF(("%s: PMF event %d injected\n",
    575 	    dv ? device_xname(dv) : "<anonymous>", ev));
    576 
    577 	return true;
    578 }
    579 
    580 bool
    581 pmf_event_register(device_t dv, pmf_generic_event_t ev,
    582     void (*handler)(device_t), bool global)
    583 {
    584 	pmf_event_handler_t *event;
    585 
    586 	event = kmem_alloc(sizeof(*event), KM_SLEEP);
    587 	event->pmf_event = ev;
    588 	event->pmf_handler = handler;
    589 	event->pmf_device = dv;
    590 	event->pmf_global = global;
    591 	TAILQ_INSERT_TAIL(&pmf_all_events, event, pmf_link);
    592 
    593 	return true;
    594 }
    595 
    596 void
    597 pmf_event_deregister(device_t dv, pmf_generic_event_t ev,
    598     void (*handler)(device_t), bool global)
    599 {
    600 	pmf_event_handler_t *event;
    601 
    602 	TAILQ_FOREACH(event, &pmf_all_events, pmf_link) {
    603 		if (event->pmf_event != ev)
    604 			continue;
    605 		if (event->pmf_device != dv)
    606 			continue;
    607 		if (event->pmf_global != global)
    608 			continue;
    609 		if (event->pmf_handler != handler)
    610 			continue;
    611 		TAILQ_REMOVE(&pmf_all_events, event, pmf_link);
    612 		kmem_free(event, sizeof(*event));
    613 		return;
    614 	}
    615 }
    616 
    617 struct display_class_softc {
    618 	TAILQ_ENTRY(display_class_softc) dc_link;
    619 	device_t dc_dev;
    620 };
    621 
    622 static TAILQ_HEAD(, display_class_softc) all_displays;
    623 static callout_t global_idle_counter;
    624 static int idle_timeout = 30;
    625 
    626 static void
    627 input_idle(void *dummy)
    628 {
    629 	PMF_IDLE_PRINTF(("Input idle handler called\n"));
    630 	pmf_event_inject(NULL, PMFE_DISPLAY_OFF);
    631 }
    632 
    633 static void
    634 input_activity_handler(device_t dv, devactive_t type)
    635 {
    636 	if (!TAILQ_EMPTY(&all_displays))
    637 		callout_schedule(&global_idle_counter, idle_timeout * hz);
    638 }
    639 
    640 static void
    641 pmf_class_input_deregister(device_t dv)
    642 {
    643 	device_active_deregister(dv, input_activity_handler);
    644 }
    645 
    646 bool
    647 pmf_class_input_register(device_t dv)
    648 {
    649 	if (!device_active_register(dv, input_activity_handler))
    650 		return false;
    651 
    652 	device_pmf_class_register(dv, NULL, NULL, NULL,
    653 	    pmf_class_input_deregister);
    654 
    655 	return true;
    656 }
    657 
    658 static void
    659 pmf_class_display_deregister(device_t dv)
    660 {
    661 	struct display_class_softc *sc = device_pmf_class_private(dv);
    662 	int s;
    663 
    664 	s = splsoftclock();
    665 	TAILQ_REMOVE(&all_displays, sc, dc_link);
    666 	if (TAILQ_EMPTY(&all_displays))
    667 		callout_stop(&global_idle_counter);
    668 	splx(s);
    669 
    670 	kmem_free(sc, sizeof(*sc));
    671 }
    672 
    673 bool
    674 pmf_class_display_register(device_t dv)
    675 {
    676 	struct display_class_softc *sc;
    677 	int s;
    678 
    679 	sc = kmem_alloc(sizeof(*sc), KM_SLEEP);
    680 
    681 	s = splsoftclock();
    682 	if (TAILQ_EMPTY(&all_displays))
    683 		callout_schedule(&global_idle_counter, idle_timeout * hz);
    684 
    685 	TAILQ_INSERT_HEAD(&all_displays, sc, dc_link);
    686 	splx(s);
    687 
    688 	device_pmf_class_register(dv, sc, NULL, NULL,
    689 	    pmf_class_display_deregister);
    690 
    691 	return true;
    692 }
    693 
    694 static void
    695 pmf_event_workitem_put(pmf_event_workitem_t *pew)
    696 {
    697 	KASSERT(pew != NULL);
    698 	pool_cache_put(pew_pc, pew);
    699 }
    700 
    701 static pmf_event_workitem_t *
    702 pmf_event_workitem_get(void)
    703 {
    704 	return pool_cache_get(pew_pc, PR_NOWAIT);
    705 }
    706 
    707 static int
    708 pew_constructor(void *arg, void *obj, int flags)
    709 {
    710 	memset(obj, 0, sizeof(pmf_event_workitem_t));
    711 	return 0;
    712 }
    713 
    714 void
    715 pmf_init(void)
    716 {
    717 	int err;
    718 
    719 	pew_pc = pool_cache_init(sizeof(pmf_event_workitem_t), 0, 0, 0,
    720 	    "pew pool", NULL, IPL_HIGH, pew_constructor, NULL, NULL);
    721 	pool_cache_setlowat(pew_pc, 16);
    722 	pool_cache_sethiwat(pew_pc, 256);
    723 
    724 	KASSERT(pmf_event_workqueue == NULL);
    725 	err = workqueue_create(&pmf_event_workqueue, "pmfevent",
    726 	    pmf_event_worker, NULL, PRI_NONE, IPL_VM, 0);
    727 	if (err)
    728 		panic("couldn't create pmfevent workqueue");
    729 
    730 	callout_init(&global_idle_counter, 0);
    731 	callout_setfunc(&global_idle_counter, input_idle, NULL);
    732 }
    733