FreeBSD/Linux Kernel Cross Reference
sys/dev/acpica/acpi_thermal.c

     /*-
      * Copyright (c) 2000, 2001 Michael Smith
      * Copyright (c) 2000 BSDi
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     * $FreeBSD: head/sys/dev/acpica/acpi_thermal.c 255077 2013-08-30 19:21:12Z dumbbell $
     */
    
    #include "opt_acpi.h"
    #include <sys/param.h>
    #include <sys/kernel.h>
    #include <sys/bus.h>
    #include <sys/kthread.h>
    #include <sys/malloc.h>
    #include <sys/module.h>
    #include <sys/proc.h>
    #include <sys/reboot.h>
    #include <sys/sysctl.h>
    #include <sys/unistd.h>
    #include <sys/power.h>
    #include <sys/sensors.h>
    
    #include <sys/mplock2.h>
    
    #include "acpi.h"
    #include "accommon.h"
    
    #include <dev/acpica/acpivar.h>
    
    /* Hooks for the ACPI CA debugging infrastructure */
    #define _COMPONENT      ACPI_THERMAL
    ACPI_MODULE_NAME("THERMAL")
    
    #define TZ_ZEROC        2732
    #define TZ_KELVTOC(x)   (((x) - TZ_ZEROC) / 10), abs(((x) - TZ_ZEROC) % 10)
    
    #define TZ_NOTIFY_TEMPERATURE   0x80 /* Temperature changed. */
    #define TZ_NOTIFY_LEVELS        0x81 /* Cooling levels changed. */
    #define TZ_NOTIFY_DEVICES       0x82 /* Device lists changed. */
    #define TZ_NOTIFY_CRITICAL      0xcc /* Fake notify that _CRT/_HOT reached. */
    
    /* Check for temperature changes every 10 seconds by default */
    #define TZ_POLLRATE     10
    
    /* Make sure the reported temperature is valid for this number of polls. */
    #define TZ_VALIDCHECKS  3
    
    /* Notify the user we will be shutting down in one more poll cycle. */
    #define TZ_NOTIFYCOUNT  (TZ_VALIDCHECKS - 1)
    
    /* ACPI spec defines this */
    #define TZ_NUMLEVELS    10
    struct acpi_tz_zone {
        int         ac[TZ_NUMLEVELS];
        ACPI_BUFFER al[TZ_NUMLEVELS];
        int         crt;
        int         hot;
        ACPI_BUFFER psl;
        int         psv;
        int         tc1;
        int         tc2;
        int         tsp;
        int         tzp;
    };
    
    struct acpi_tz_softc {
        device_t                    tz_dev;
        ACPI_HANDLE                 tz_handle;      /*Thermal zone handle*/
        int                         tz_temperature; /*Current temperature*/
        int                         tz_active;      /*Current active cooling*/
    #define TZ_ACTIVE_NONE          -1
    #define TZ_ACTIVE_UNKNOWN       -2
        int                         tz_requested;   /*Minimum active cooling*/
        int                         tz_thflags;     /*Current temp-related flags*/
    #define TZ_THFLAG_NONE          0
    #define TZ_THFLAG_PSV           (1<<0)
    #define TZ_THFLAG_HOT           (1<<2)
    #define TZ_THFLAG_CRT           (1<<3)
       int                         tz_flags;
   #define TZ_FLAG_NO_SCP          (1<<0)          /*No _SCP method*/
   #define TZ_FLAG_GETPROFILE      (1<<1)          /*Get power_profile in timeout*/
   #define TZ_FLAG_GETSETTINGS     (1<<2)          /*Get devs/setpoints*/
       struct timespec             tz_cooling_started;
                                           /*Current cooling starting time*/
   
       struct sysctl_ctx_list      tz_sysctl_ctx;
       struct sysctl_oid           *tz_sysctl_tree;
       eventhandler_tag            tz_event;
   
       struct acpi_tz_zone         tz_zone;        /*Thermal zone parameters*/
       int                         tz_validchecks;
       int                         tz_insane_tmp_notified;
   
       /* passive cooling */
       struct thread               *tz_cooling_proc;
       int                         tz_cooling_proc_running;
       int                         tz_cooling_enabled;
       int                         tz_cooling_active;
       int                         tz_cooling_updated;
       int                         tz_cooling_saved_freq;
       /* sensors(9) related */
       struct ksensordev           sensordev;
       struct ksensor              sensor;
   };
   
   #define TZ_ACTIVE_LEVEL(act)    ((act) >= 0 ? (act) : TZ_NUMLEVELS)
   
   #define CPUFREQ_MAX_LEVELS      64 /* XXX cpufreq should export this */
   
   static int      acpi_tz_probe(device_t dev);
   static int      acpi_tz_attach(device_t dev);
   static int      acpi_tz_establish(struct acpi_tz_softc *sc);
   static void     acpi_tz_monitor(void *Context);
   static void     acpi_tz_switch_cooler_off(ACPI_OBJECT *obj, void *arg);
   static void     acpi_tz_switch_cooler_on(ACPI_OBJECT *obj, void *arg);
   static void     acpi_tz_getparam(struct acpi_tz_softc *sc, char *node,
                                    int *data);
   static void     acpi_tz_sanity(struct acpi_tz_softc *sc, int *val, char *what);
   static int      acpi_tz_active_sysctl(SYSCTL_HANDLER_ARGS);
   static int      acpi_tz_cooling_sysctl(SYSCTL_HANDLER_ARGS);
   static int      acpi_tz_temp_sysctl(SYSCTL_HANDLER_ARGS);
   static int      acpi_tz_passive_sysctl(SYSCTL_HANDLER_ARGS);
   static void     acpi_tz_notify_handler(ACPI_HANDLE h, UINT32 notify,
                                          void *context);
   static void     acpi_tz_signal(struct acpi_tz_softc *sc, int flags);
   static void     acpi_tz_timeout(struct acpi_tz_softc *sc, int flags);
   static void     acpi_tz_power_profile(void *arg);
   static void     acpi_tz_thread(void *arg);
   static int      acpi_tz_cooling_is_available(struct acpi_tz_softc *sc);
   static int      acpi_tz_cooling_thread_start(struct acpi_tz_softc *sc);
   
   static device_method_t acpi_tz_methods[] = {
       /* Device interface */
       DEVMETHOD(device_probe,     acpi_tz_probe),
       DEVMETHOD(device_attach,    acpi_tz_attach),
   
       DEVMETHOD_END
   };
   
   static driver_t acpi_tz_driver = {
       "acpi_tz",
       acpi_tz_methods,
       sizeof(struct acpi_tz_softc),
   };
   
   static char *acpi_tz_tmp_name = "_TMP";
   
   static devclass_t acpi_tz_devclass;
   DRIVER_MODULE(acpi_tz, acpi, acpi_tz_driver, acpi_tz_devclass, NULL, NULL);
   MODULE_DEPEND(acpi_tz, acpi, 1, 1, 1);
   
   static struct sysctl_ctx_list   acpi_tz_sysctl_ctx;
   static struct sysctl_oid        *acpi_tz_sysctl_tree;
   
   /* Minimum cooling run time */
   static int                      acpi_tz_min_runtime;
   static int                      acpi_tz_polling_rate = TZ_POLLRATE;
   static int                      acpi_tz_override;
   
   /* Timezone polling thread */
   static struct thread            *acpi_tz_td;
   ACPI_LOCK_DECL(thermal, "ACPI thermal zone");
   
   static int                      acpi_tz_cooling_unit = -1;
   
   static int
   acpi_tz_probe(device_t dev)
   {
       int         result;
   
       if (acpi_get_type(dev) == ACPI_TYPE_THERMAL && !acpi_disabled("thermal")) {
           device_set_desc(dev, "Thermal Zone");
           result = -10;
       } else
           result = ENXIO;
       return (result);
   }
   
   static int
   acpi_tz_attach(device_t dev)
   {
       struct acpi_tz_softc        *sc;
       struct acpi_softc           *acpi_sc;
       int                         error;
       char                        oidname[8];
   
       ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
   
       sc = device_get_softc(dev);
       sc->tz_dev = dev;
       sc->tz_handle = acpi_get_handle(dev);
       sc->tz_requested = TZ_ACTIVE_NONE;
       sc->tz_active = TZ_ACTIVE_UNKNOWN;
       sc->tz_thflags = TZ_THFLAG_NONE;
       sc->tz_cooling_proc = NULL;
       sc->tz_cooling_proc_running = FALSE;
       sc->tz_cooling_active = FALSE;
       sc->tz_cooling_updated = FALSE;
       sc->tz_cooling_enabled = FALSE;
   
       /*
        * Parse the current state of the thermal zone and build control
        * structures.  We don't need to worry about interference with the
        * control thread since we haven't fully attached this device yet.
        */
       if ((error = acpi_tz_establish(sc)) != 0)
           return (error);
   
       /*
        * Register for any Notify events sent to this zone.
        */
       AcpiInstallNotifyHandler(sc->tz_handle, ACPI_DEVICE_NOTIFY,
                                acpi_tz_notify_handler, sc);
   
       /*
        * Create our sysctl nodes.
        *
        * XXX we need a mechanism for adding nodes under ACPI.
        */
       if (device_get_unit(dev) == 0) {
           acpi_sc = acpi_device_get_parent_softc(dev);
           sysctl_ctx_init(&acpi_tz_sysctl_ctx);
           acpi_tz_sysctl_tree = SYSCTL_ADD_NODE(&acpi_tz_sysctl_ctx,
                                 SYSCTL_CHILDREN(acpi_sc->acpi_sysctl_tree),
                                 OID_AUTO, "thermal", CTLFLAG_RD, 0, "");
           SYSCTL_ADD_INT(&acpi_tz_sysctl_ctx,
                          SYSCTL_CHILDREN(acpi_tz_sysctl_tree),
                          OID_AUTO, "min_runtime", CTLFLAG_RW,
                          &acpi_tz_min_runtime, 0,
                          "minimum cooling run time in sec");
           SYSCTL_ADD_INT(&acpi_tz_sysctl_ctx,
                          SYSCTL_CHILDREN(acpi_tz_sysctl_tree),
                          OID_AUTO, "polling_rate", CTLFLAG_RW,
                          &acpi_tz_polling_rate, 0, "monitor polling interval in seconds");
           SYSCTL_ADD_INT(&acpi_tz_sysctl_ctx,
                          SYSCTL_CHILDREN(acpi_tz_sysctl_tree), OID_AUTO,
                          "user_override", CTLFLAG_RW, &acpi_tz_override, 0,
                          "allow override of thermal settings");
       }
       sysctl_ctx_init(&sc->tz_sysctl_ctx);
       ksprintf(oidname, "tz%d", device_get_unit(dev));
       sc->tz_sysctl_tree = SYSCTL_ADD_NODE(&sc->tz_sysctl_ctx,
                                            SYSCTL_CHILDREN(acpi_tz_sysctl_tree),
                                            OID_AUTO, oidname, CTLFLAG_RD, 0, "");
       SYSCTL_ADD_PROC(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
                       OID_AUTO, "temperature", CTLTYPE_INT | CTLFLAG_RD,
                       &sc->tz_temperature, 0, sysctl_handle_int,
                       "IK", "current thermal zone temperature");
       SYSCTL_ADD_PROC(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
                       OID_AUTO, "active", CTLTYPE_INT | CTLFLAG_RW,
                       sc, 0, acpi_tz_active_sysctl, "I", "cooling is active");
       SYSCTL_ADD_PROC(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
                       OID_AUTO, "passive_cooling", CTLTYPE_INT | CTLFLAG_RW,
                       sc, 0, acpi_tz_cooling_sysctl, "I",
                       "enable passive (speed reduction) cooling");
   
       SYSCTL_ADD_INT(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
                      OID_AUTO, "thermal_flags", CTLFLAG_RD,
                      &sc->tz_thflags, 0, "thermal zone flags");
       SYSCTL_ADD_PROC(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
                       OID_AUTO, "_PSV", CTLTYPE_INT | CTLFLAG_RW,
                       sc, offsetof(struct acpi_tz_softc, tz_zone.psv),
                       acpi_tz_temp_sysctl, "IK", "passive cooling temp setpoint");
       SYSCTL_ADD_PROC(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
                       OID_AUTO, "_HOT", CTLTYPE_INT | CTLFLAG_RW,
                       sc, offsetof(struct acpi_tz_softc, tz_zone.hot),
                       acpi_tz_temp_sysctl, "IK",
                       "too hot temp setpoint (suspend now)");
       SYSCTL_ADD_PROC(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
                       OID_AUTO, "_CRT", CTLTYPE_INT | CTLFLAG_RW,
                       sc, offsetof(struct acpi_tz_softc, tz_zone.crt),
                       acpi_tz_temp_sysctl, "IK",
                       "critical temp setpoint (shutdown now)");
       SYSCTL_ADD_PROC(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
                       OID_AUTO, "_ACx", CTLTYPE_INT | CTLFLAG_RD,
                       &sc->tz_zone.ac, sizeof(sc->tz_zone.ac),
                       sysctl_handle_opaque, "IK", "");
       SYSCTL_ADD_PROC(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
                       OID_AUTO, "_TC1", CTLTYPE_INT | CTLFLAG_RW,
                       sc, offsetof(struct acpi_tz_softc, tz_zone.tc1),
                       acpi_tz_passive_sysctl, "I",
                       "thermal constant 1 for passive cooling");
       SYSCTL_ADD_PROC(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
                       OID_AUTO, "_TC2", CTLTYPE_INT | CTLFLAG_RW,
                       sc, offsetof(struct acpi_tz_softc, tz_zone.tc2),
                       acpi_tz_passive_sysctl, "I",
                       "thermal constant 2 for passive cooling");
       SYSCTL_ADD_PROC(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
                       OID_AUTO, "_TSP", CTLTYPE_INT | CTLFLAG_RW,
                       sc, offsetof(struct acpi_tz_softc, tz_zone.tsp),
                       acpi_tz_passive_sysctl, "I",
                       "thermal sampling period for passive cooling");
   
       /*
        * Create thread to service all of the thermal zones.  Register
        * our power profile event handler.
        */
       sc->tz_event = EVENTHANDLER_REGISTER(power_profile_change,
           acpi_tz_power_profile, sc, 0);
       if (acpi_tz_td == NULL) {
           error = kthread_create(acpi_tz_thread, NULL, &acpi_tz_td,
               "acpi_thermal");
           if (error != 0) {
               device_printf(sc->tz_dev, "could not create thread - %d", error);
               goto out;
           }
       }
   
       /*
        * Create a thread to handle passive cooling for 1st zone which
        * has _PSV, _TSP, _TC1 and _TC2.  Users can enable it for other
        * zones manually for now.
        *
        * XXX We enable only one zone to avoid multiple zones conflict
        * with each other since cpufreq currently sets all CPUs to the
        * given frequency whereas it's possible for different thermal
        * zones to specify independent settings for multiple CPUs.
        */
       if (acpi_tz_cooling_unit < 0 && acpi_tz_cooling_is_available(sc))
           sc->tz_cooling_enabled = TRUE;
       if (sc->tz_cooling_enabled) {
           error = acpi_tz_cooling_thread_start(sc);
           if (error != 0) {
               sc->tz_cooling_enabled = FALSE;
               goto out;
           }
           acpi_tz_cooling_unit = device_get_unit(dev);
       }
   
       /*
        * Flag the event handler for a manual invocation by our timeout.
        * We defer it like this so that the rest of the subsystem has time
        * to come up.  Don't bother evaluating/printing the temperature at
        * this point; on many systems it'll be bogus until the EC is running.
        */
       sc->tz_flags |= TZ_FLAG_GETPROFILE;
   
       /* Attach sensors(9). */
       strlcpy(sc->sensordev.xname, device_get_nameunit(sc->tz_dev),
           sizeof(sc->sensordev.xname));
   
       sc->sensor.type = SENSOR_TEMP;
       sensor_attach(&sc->sensordev, &sc->sensor);
   
       sensordev_install(&sc->sensordev);
   
   out:
       if (error != 0) {
           EVENTHANDLER_DEREGISTER(power_profile_change, sc->tz_event);
           AcpiRemoveNotifyHandler(sc->tz_handle, ACPI_DEVICE_NOTIFY,
               acpi_tz_notify_handler);
           sysctl_ctx_free(&sc->tz_sysctl_ctx);
       }
       return_VALUE (error);
   }
   
   /*
    * Parse the current state of this thermal zone and set up to use it.
    *
    * Note that we may have previous state, which will have to be discarded.
    */
   static int
   acpi_tz_establish(struct acpi_tz_softc *sc)
   {
       ACPI_OBJECT *obj;
       int         i;
       char        nbuf[8];
   
       ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
   
       /* Erase any existing state. */
       for (i = 0; i < TZ_NUMLEVELS; i++)
           if (sc->tz_zone.al[i].Pointer != NULL)
               AcpiOsFree(sc->tz_zone.al[i].Pointer);
       if (sc->tz_zone.psl.Pointer != NULL)
           AcpiOsFree(sc->tz_zone.psl.Pointer);
   
       /*
        * XXX: We initialize only ACPI_BUFFER to avoid race condition
        * with passive cooling thread which refers psv, tc1, tc2 and tsp.
        */
       bzero(sc->tz_zone.ac, sizeof(sc->tz_zone.ac));
       bzero(sc->tz_zone.al, sizeof(sc->tz_zone.al));
       bzero(&sc->tz_zone.psl, sizeof(sc->tz_zone.psl));
   
       /* Evaluate thermal zone parameters. */
       for (i = 0; i < TZ_NUMLEVELS; i++) {
           ksprintf(nbuf, "_AC%d", i);
           acpi_tz_getparam(sc, nbuf, &sc->tz_zone.ac[i]);
           ksprintf(nbuf, "_AL%d", i);
           sc->tz_zone.al[i].Length = ACPI_ALLOCATE_BUFFER;
           sc->tz_zone.al[i].Pointer = NULL;
           AcpiEvaluateObject(sc->tz_handle, nbuf, NULL, &sc->tz_zone.al[i]);
           obj = (ACPI_OBJECT *)sc->tz_zone.al[i].Pointer;
           if (obj != NULL) {
               /* Should be a package containing a list of power objects */
               if (obj->Type != ACPI_TYPE_PACKAGE) {
                   device_printf(sc->tz_dev, "%s has unknown type %d, rejecting\n",
                                 nbuf, obj->Type);
                   return_VALUE (ENXIO);
               }
           }
       }
       acpi_tz_getparam(sc, "_CRT", &sc->tz_zone.crt);
       acpi_tz_getparam(sc, "_HOT", &sc->tz_zone.hot);
       sc->tz_zone.psl.Length = ACPI_ALLOCATE_BUFFER;
       sc->tz_zone.psl.Pointer = NULL;
       AcpiEvaluateObject(sc->tz_handle, "_PSL", NULL, &sc->tz_zone.psl);
       acpi_tz_getparam(sc, "_PSV", &sc->tz_zone.psv);
       acpi_tz_getparam(sc, "_TC1", &sc->tz_zone.tc1);
       acpi_tz_getparam(sc, "_TC2", &sc->tz_zone.tc2);
       acpi_tz_getparam(sc, "_TSP", &sc->tz_zone.tsp);
       acpi_tz_getparam(sc, "_TZP", &sc->tz_zone.tzp);
   
       /*
        * Sanity-check the values we've been given.
        *
        * XXX what do we do about systems that give us the same value for
        *     more than one of these setpoints?
        */
       acpi_tz_sanity(sc, &sc->tz_zone.crt, "_CRT");
       acpi_tz_sanity(sc, &sc->tz_zone.hot, "_HOT");
       acpi_tz_sanity(sc, &sc->tz_zone.psv, "_PSV");
       for (i = 0; i < TZ_NUMLEVELS; i++)
           acpi_tz_sanity(sc, &sc->tz_zone.ac[i], "_ACx");
   
       return_VALUE (0);
   }
   
   static char *aclevel_string[] = {
       "NONE", "_AC0", "_AC1", "_AC2", "_AC3", "_AC4",
       "_AC5", "_AC6", "_AC7", "_AC8", "_AC9"
   };
   
   static __inline const char *
   acpi_tz_aclevel_string(int active)
   {
       if (active < -1 || active >= TZ_NUMLEVELS)
           return (aclevel_string[0]);
   
       return (aclevel_string[active + 1]);
   }
   
   /*
    * Get the current temperature.
    */
   static int
   acpi_tz_get_temperature(struct acpi_tz_softc *sc)
   {
       int         temp;
       ACPI_STATUS status;
   
       ACPI_FUNCTION_NAME ("acpi_tz_get_temperature");
   
       /* Evaluate the thermal zone's _TMP method. */
       status = acpi_GetInteger(sc->tz_handle, acpi_tz_tmp_name, &temp);
       if (ACPI_FAILURE(status)) {
           ACPI_VPRINT(sc->tz_dev, acpi_device_get_parent_softc(sc->tz_dev),
               "error fetching current temperature -- %s\n",
                AcpiFormatException(status));
           return (FALSE);
       }
   
       /* Check it for validity. */
       acpi_tz_sanity(sc, &temp, acpi_tz_tmp_name);
       if (temp == -1)
           return (FALSE);
   
       ACPI_DEBUG_PRINT((ACPI_DB_VALUES, "got %d.%dC\n", TZ_KELVTOC(temp)));
       sc->tz_temperature = temp;
       /* Update sensor */
       if(sc->tz_temperature == -1)
           sc->sensor.flags &= ~SENSOR_FINVALID;
       sc->sensor.value = sc->tz_temperature * 100000 - 50000;
       return (TRUE);
   }
   
   /*
    * Evaluate the condition of a thermal zone, take appropriate actions.
    */
   static void
   acpi_tz_monitor(void *Context)
   {
       struct acpi_tz_softc *sc;
       struct      timespec curtime;
       int         temp;
       int         i;
       int         newactive, newflags;
   
       ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
   
       sc = (struct acpi_tz_softc *)Context;
   
       /* Get the current temperature. */
       if (!acpi_tz_get_temperature(sc)) {
           /* XXX disable zone? go to max cooling? */
           return_VOID;
       }
       temp = sc->tz_temperature;
   
       /*
        * Work out what we ought to be doing right now.
        *
        * Note that the _ACx levels sort from hot to cold.
        */
       newactive = TZ_ACTIVE_NONE;
       for (i = TZ_NUMLEVELS - 1; i >= 0; i--) {
           if (sc->tz_zone.ac[i] != -1 && temp >= sc->tz_zone.ac[i])
               newactive = i;
       }
   
       /*
        * We are going to get _ACx level down (colder side), but give a guaranteed
        * minimum cooling run time if requested.
        */
       if (acpi_tz_min_runtime > 0 && sc->tz_active != TZ_ACTIVE_NONE &&
           sc->tz_active != TZ_ACTIVE_UNKNOWN &&
           (newactive == TZ_ACTIVE_NONE || newactive > sc->tz_active)) {
   
           getnanotime(&curtime);
           timespecsub(&curtime, &sc->tz_cooling_started);
           if (curtime.tv_sec < acpi_tz_min_runtime)
               newactive = sc->tz_active;
       }
   
       /* Handle user override of active mode */
       if (sc->tz_requested != TZ_ACTIVE_NONE && (newactive == TZ_ACTIVE_NONE
           || sc->tz_requested < newactive))
           newactive = sc->tz_requested;
   
       /* update temperature-related flags */
       newflags = TZ_THFLAG_NONE;
       if (sc->tz_zone.psv != -1 && temp >= sc->tz_zone.psv)
           newflags |= TZ_THFLAG_PSV;
       if (sc->tz_zone.hot != -1 && temp >= sc->tz_zone.hot)
           newflags |= TZ_THFLAG_HOT;
       if (sc->tz_zone.crt != -1 && temp >= sc->tz_zone.crt)
           newflags |= TZ_THFLAG_CRT;
   
       /* If the active cooling state has changed, we have to switch things. */
       if (sc->tz_active == TZ_ACTIVE_UNKNOWN) {
           /*
            * We don't know which cooling device is on or off,
            * so stop them all, because we now know which
            * should be on (if any).
            */
           for (i = 0; i < TZ_NUMLEVELS; i++) {
               if (sc->tz_zone.al[i].Pointer != NULL) {
                   acpi_ForeachPackageObject(
                       (ACPI_OBJECT *)sc->tz_zone.al[i].Pointer,
                       acpi_tz_switch_cooler_off, sc);
               }
           }
           /* now we know that all devices are off */
           sc->tz_active = TZ_ACTIVE_NONE;
       }
   
       if (newactive != sc->tz_active) {
           /* Turn off unneeded cooling devices that are on, if any are */
           for (i = TZ_ACTIVE_LEVEL(sc->tz_active);
                i < TZ_ACTIVE_LEVEL(newactive); i++) {
               acpi_ForeachPackageObject(
                   (ACPI_OBJECT *)sc->tz_zone.al[i].Pointer,
                   acpi_tz_switch_cooler_off, sc);
           }
           /* Turn on cooling devices that are required, if any are */
           for (i = TZ_ACTIVE_LEVEL(sc->tz_active) - 1;
                i >= TZ_ACTIVE_LEVEL(newactive); i--) {
               acpi_ForeachPackageObject(
                   (ACPI_OBJECT *)sc->tz_zone.al[i].Pointer,
                   acpi_tz_switch_cooler_on, sc);
           }
   
           ACPI_VPRINT(sc->tz_dev, acpi_device_get_parent_softc(sc->tz_dev),
                       "switched from %s to %s: %d.%dC\n",
                       acpi_tz_aclevel_string(sc->tz_active),
                       acpi_tz_aclevel_string(newactive), TZ_KELVTOC(temp));
           sc->tz_active = newactive;
           getnanotime(&sc->tz_cooling_started);
       }
   
       /* XXX (de)activate any passive cooling that may be required. */
   
       /*
        * If the temperature is at _HOT or _CRT, increment our event count.
        * If it has occurred enough times, shutdown the system.  This is
        * needed because some systems will report an invalid high temperature
        * for one poll cycle.  It is suspected this is due to the embedded
        * controller timing out.  A typical value is 138C for one cycle on
        * a system that is otherwise 65C.
        *
        * If we're almost at that threshold, notify the user through devd(8).
        */
       if ((newflags & (TZ_THFLAG_HOT | TZ_THFLAG_CRT)) != 0) {
           sc->tz_validchecks++;
           if (sc->tz_validchecks == TZ_VALIDCHECKS) {
               device_printf(sc->tz_dev,
                   "WARNING - current temperature (%d.%dC) exceeds safe limits\n",
                   TZ_KELVTOC(sc->tz_temperature));
               shutdown_nice(RB_POWEROFF);
           } else if (sc->tz_validchecks == TZ_NOTIFYCOUNT)
               acpi_UserNotify("Thermal", sc->tz_handle, TZ_NOTIFY_CRITICAL);
       } else {
           sc->tz_validchecks = 0;
       }
       sc->tz_thflags = newflags;
   
       return_VOID;
   }
   
   /*
    * Given an object, verify that it's a reference to a device of some sort,
    * and try to switch it off.
    */
   static void
   acpi_tz_switch_cooler_off(ACPI_OBJECT *obj, void *arg)
   {
       ACPI_HANDLE                 cooler;
   
       ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
   
       cooler = acpi_GetReference(NULL, obj);
       if (cooler == NULL) {
           ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "can't get handle\n"));
           return_VOID;
       }
   
       ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "called to turn %s off\n",
                        acpi_name(cooler)));
       acpi_pwr_switch_consumer(cooler, ACPI_STATE_D3);
   
       return_VOID;
   }
   
   /*
    * Given an object, verify that it's a reference to a device of some sort,
    * and try to switch it on.
    *
    * XXX replication of off/on function code is bad.
    */
   static void
   acpi_tz_switch_cooler_on(ACPI_OBJECT *obj, void *arg)
   {
       struct acpi_tz_softc        *sc = (struct acpi_tz_softc *)arg;
       ACPI_HANDLE                 cooler;
       ACPI_STATUS                 status;
   
       ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
   
       cooler = acpi_GetReference(NULL, obj);
       if (cooler == NULL) {
           ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "can't get handle\n"));
           return_VOID;
       }
   
       ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "called to turn %s on\n",
                        acpi_name(cooler)));
       status = acpi_pwr_switch_consumer(cooler, ACPI_STATE_D0);
       if (ACPI_FAILURE(status)) {
           ACPI_VPRINT(sc->tz_dev, acpi_device_get_parent_softc(sc->tz_dev),
                       "failed to activate %s - %s\n", acpi_name(cooler),
                       AcpiFormatException(status));
       }
   
       return_VOID;
   }
   
   /*
    * Read/debug-print a parameter, default it to -1.
    */
   static void
   acpi_tz_getparam(struct acpi_tz_softc *sc, char *node, int *data)
   {
   
       ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
   
       if (ACPI_FAILURE(acpi_GetInteger(sc->tz_handle, node, data))) {
           *data = -1;
       } else {
           ACPI_DEBUG_PRINT((ACPI_DB_VALUES, "%s.%s = %d\n",
                            acpi_name(sc->tz_handle), node, *data));
       }
   
       return_VOID;
   }
   
   /*
    * Sanity-check a temperature value.  Assume that setpoints
    * should be between 0C and 200C.
    */
   static void
   acpi_tz_sanity(struct acpi_tz_softc *sc, int *val, char *what)
   {
       if (*val != -1 && (*val < TZ_ZEROC || *val > TZ_ZEROC + 2000)) {
           /*
            * If the value we are checking is _TMP, warn the user only
            * once. This avoids spamming messages if, for instance, the
            * sensor is broken and always returns an invalid temperature.
            *
            * This is only done for _TMP; other values always emit a
            * warning.
            */
           if (what != acpi_tz_tmp_name || !sc->tz_insane_tmp_notified) {
               device_printf(sc->tz_dev, "%s value is absurd, ignored (%d.%dC)\n",
                             what, TZ_KELVTOC(*val));
   
               /* Don't warn the user again if the read value doesn't improve. */
               if (what == acpi_tz_tmp_name)
                   sc->tz_insane_tmp_notified = 1;
           }
           *val = -1;
           return;
       }
   
       /* This value is correct. Warn if it's incorrect again. */
       if (what == acpi_tz_tmp_name)
           sc->tz_insane_tmp_notified = 0;
   }
   
   /*
    * Respond to a sysctl on the active state node.
    */
   static int
   acpi_tz_active_sysctl(SYSCTL_HANDLER_ARGS)
   {
       struct acpi_tz_softc        *sc;
       int                         active;
       int                         error;
   
       sc = (struct acpi_tz_softc *)oidp->oid_arg1;
       active = sc->tz_active;
       error = sysctl_handle_int(oidp, &active, 0, req);
   
       /* Error or no new value */
       if (error != 0 || req->newptr == NULL)
           return (error);
       if (active < -1 || active >= TZ_NUMLEVELS)
           return (EINVAL);
   
       /* Set new preferred level and re-switch */
       sc->tz_requested = active;
       acpi_tz_signal(sc, 0);
       return (0);
   }
   
   static int
   acpi_tz_cooling_sysctl(SYSCTL_HANDLER_ARGS)
   {
       struct acpi_tz_softc *sc;
       int enabled, error;
   
       sc = (struct acpi_tz_softc *)oidp->oid_arg1;
       enabled = sc->tz_cooling_enabled;
       error = sysctl_handle_int(oidp, &enabled, 0, req);
   
       /* Error or no new value */
       if (error != 0 || req->newptr == NULL)
           return (error);
       if (enabled != TRUE && enabled != FALSE)
           return (EINVAL);
   
       if (enabled) {
           if (acpi_tz_cooling_is_available(sc))
               error = acpi_tz_cooling_thread_start(sc);
           else
               error = ENODEV;
           if (error)
               enabled = FALSE;
       }
       sc->tz_cooling_enabled = enabled;
       return (error);
   }
   
   static int
   acpi_tz_temp_sysctl(SYSCTL_HANDLER_ARGS)
   {
       struct acpi_tz_softc        *sc;
       int                         temp, *temp_ptr;
       int                         error;
   
       sc = oidp->oid_arg1;
       temp_ptr = (int *)((uintptr_t)sc + oidp->oid_arg2);
       temp = *temp_ptr;
       error = sysctl_handle_int(oidp, &temp, 0, req);
   
       /* Error or no new value */
       if (error != 0 || req->newptr == NULL)
           return (error);
   
       /* Only allow changing settings if override is set. */
       if (!acpi_tz_override)
           return (EPERM);
   
       /* Check user-supplied value for sanity. */
       acpi_tz_sanity(sc, &temp, "user-supplied temp");
       if (temp == -1)
           return (EINVAL);
   
       *temp_ptr = temp;
       return (0);
   }
   
   static int
   acpi_tz_passive_sysctl(SYSCTL_HANDLER_ARGS)
   {
       struct acpi_tz_softc        *sc;
       int                         val, *val_ptr;
       int                         error;
   
       sc = oidp->oid_arg1;
       val_ptr = (int *)((uintptr_t)sc + oidp->oid_arg2);
       val = *val_ptr;
       error = sysctl_handle_int(oidp, &val, 0, req);
   
       /* Error or no new value */
       if (error != 0 || req->newptr == NULL)
           return (error);
   
       /* Only allow changing settings if override is set. */
       if (!acpi_tz_override)
           return (EPERM);
   
       *val_ptr = val;
       return (0);
   }
   
   static void
   acpi_tz_notify_handler(ACPI_HANDLE h, UINT32 notify, void *context)
   {
       struct acpi_tz_softc        *sc = (struct acpi_tz_softc *)context;
   
       ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
   
       switch (notify) {
       case TZ_NOTIFY_TEMPERATURE:
           /* Temperature change occurred */
           acpi_tz_signal(sc, 0);
           break;
       case TZ_NOTIFY_DEVICES:
       case TZ_NOTIFY_LEVELS:
           /* Zone devices/setpoints changed */
           acpi_tz_signal(sc, TZ_FLAG_GETSETTINGS);
           break;
       default:
           ACPI_VPRINT(sc->tz_dev, acpi_device_get_parent_softc(sc->tz_dev),
                       "unknown Notify event 0x%x\n", notify);
           break;
       }
   
       acpi_UserNotify("Thermal", h, notify);
   
       return_VOID;
   }
   
   static void
   acpi_tz_signal(struct acpi_tz_softc *sc, int flags)
   {
       ACPI_LOCK(thermal);
       sc->tz_flags |= flags;
       ACPI_UNLOCK(thermal);
       wakeup(&acpi_tz_td);
   }
   
   /*
    * Notifies can be generated asynchronously but have also been seen to be
    * triggered by other thermal methods.  One system generates a notify of
    * 0x81 when the fan is turned on or off.  Another generates it when _SCP
    * is called.  To handle these situations, we check the zone via
    * acpi_tz_monitor() before evaluating changes to setpoints or the cooling
    * policy.
    */
   static void
   acpi_tz_timeout(struct acpi_tz_softc *sc, int flags)
   {
   
       /* Check the current temperature and take action based on it */
       acpi_tz_monitor(sc);
   
       /* If requested, get the power profile settings. */
       if (flags & TZ_FLAG_GETPROFILE)
           acpi_tz_power_profile(sc);
   
       /*
        * If requested, check for new devices/setpoints.  After finding them,
        * check if we need to switch fans based on the new values.
        */
       if (flags & TZ_FLAG_GETSETTINGS) {
           acpi_tz_establish(sc);
           acpi_tz_monitor(sc);
       }
   
       /* XXX passive cooling actions? */
   }
   
   /*
    * System power profile may have changed; fetch and notify the
    * thermal zone accordingly.
    *
    * Since this can be called from an arbitrary eventhandler, it needs
    * to get the ACPI lock itself.
    */
   static void
   acpi_tz_power_profile(void *arg)
   {
       ACPI_STATUS                 status;
       struct acpi_tz_softc        *sc = (struct acpi_tz_softc *)arg;
       int                         state;
   
       state = power_profile_get_state();
       if (state != POWER_PROFILE_PERFORMANCE && state != POWER_PROFILE_ECONOMY)
           return;
   
       /* check that we haven't decided there's no _SCP method */
       if ((sc->tz_flags & TZ_FLAG_NO_SCP) == 0) {
   
           /* Call _SCP to set the new profile */
           status = acpi_SetInteger(sc->tz_handle, "_SCP",
               (state == POWER_PROFILE_PERFORMANCE) ? 0 : 1);
           if (ACPI_FAILURE(status)) {
               if (status != AE_NOT_FOUND)
                   ACPI_VPRINT(sc->tz_dev,
                               acpi_device_get_parent_softc(sc->tz_dev),
                               "can't evaluate %s._SCP - %s\n",
                               acpi_name(sc->tz_handle),
                               AcpiFormatException(status));
               sc->tz_flags |= TZ_FLAG_NO_SCP;
           } else {
               /* We have to re-evaluate the entire zone now */
               acpi_tz_signal(sc, TZ_FLAG_GETSETTINGS);
           }
       }
   }
   
   /*
    * Thermal zone monitor thread.
    */
   static void
   acpi_tz_thread(void *arg)
   {
       device_t    *devs;
       int         devcount, i;
       int         flags;
       struct acpi_tz_softc **sc;
   
       ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
   
       devs = NULL;
       devcount = 0;
       sc = NULL;
       get_mplock();
   
       for (;;) {
           /* If the number of devices has changed, re-evaluate. */
           if (devclass_get_count(acpi_tz_devclass) != devcount) {
               if (devs != NULL) {
                   kfree(devs, M_TEMP);
                   kfree(sc, M_TEMP);
               }
               devclass_get_devices(acpi_tz_devclass, &devs, &devcount);
               sc = kmalloc(sizeof(struct acpi_tz_softc *) * devcount, M_TEMP,
                           M_WAITOK | M_ZERO);
               for (i = 0; i < devcount; i++)
                   sc[i] = device_get_softc(devs[i]);
           }
   
           /* Check for temperature events and act on them. */
           for (i = 0; i < devcount; i++) {
               ACPI_LOCK(thermal);
               flags = sc[i]->tz_flags;
               sc[i]->tz_flags &= TZ_FLAG_NO_SCP;
               ACPI_UNLOCK(thermal);
               acpi_tz_timeout(sc[i], flags);
           }
   
           /* If more work to do, don't go to sleep yet. */
           ACPI_LOCK(thermal);
           for (i = 0; i < devcount; i++) {
               if (sc[i]->tz_flags & ~TZ_FLAG_NO_SCP)
                  break;
          }
  
          /*
           * Interlocked sleep until signaled or we timeout.
           */
          if (i == devcount) {
              tsleep_interlock(&acpi_tz_td, 0);
              ACPI_UNLOCK(thermal);
              tsleep(&acpi_tz_td, 0, "tzpoll", hz * acpi_tz_polling_rate);
          } else {
              ACPI_UNLOCK(thermal);
          }
      }
      rel_mplock();
  }
  
  #ifdef __FreeBSD__
  static int
  acpi_tz_cpufreq_restore(struct acpi_tz_softc *sc)
  {
      device_t dev;
      int error;
  
      if (!sc->tz_cooling_updated)
          return (0);
      if ((dev = devclass_get_device(devclass_find("cpufreq"), 0)) == NULL)
          return (ENXIO);
      ACPI_VPRINT(sc->tz_dev, acpi_device_get_parent_softc(sc->tz_dev),
          "temperature %d.%dC: resuming previous clock speed (%d MHz)\n",
          TZ_KELVTOC(sc->tz_temperature), sc->tz_cooling_saved_freq);
      error = CPUFREQ_SET(dev, NULL, CPUFREQ_PRIO_KERN);
      if (error == 0)
          sc->tz_cooling_updated = FALSE;
      return (error);
  }
  
  static int
  acpi_tz_cpufreq_update(struct acpi_tz_softc *sc, int req)
  {
      device_t dev;
      struct cf_level *levels;
      int num_levels, error, freq, desired_freq, perf, i;
  
      levels = kmalloc(CPUFREQ_MAX_LEVELS * sizeof(*levels), M_TEMP, M_NOWAIT);
      if (levels == NULL)
          return (ENOMEM);
  
      /*
       * Find the main device, cpufreq0.  We don't yet support independent
       * CPU frequency control on SMP.
       */
      if ((dev = devclass_get_device(devclass_find("cpufreq"), 0)) == NULL) {
          error = ENXIO;
          goto out;
      }
  
      /* Get the current frequency. */
      error = CPUFREQ_GET(dev, &levels[0]);
      if (error)
          goto out;
      freq = levels[0].total_set.freq;
  
      /* Get the current available frequency levels. */
      num_levels = CPUFREQ_MAX_LEVELS;
      error = CPUFREQ_LEVELS(dev, levels, &num_levels);
      if (error) {
          if (error == E2BIG)
              printf("cpufreq: need to increase CPUFREQ_MAX_LEVELS\n");
          goto out;
      }
  
      /* Calculate the desired frequency as a percent of the max frequency. */
      perf = 100 * freq / levels[0].total_set.freq - req;
      if (perf < 0)
          perf = 0;
      else if (perf > 100)
          perf = 100;
      desired_freq = levels[0].total_set.freq * perf / 100;
  
      if (desired_freq < freq) {
          /* Find the closest available frequency, rounding down. */
          for (i = 0; i < num_levels; i++)
              if (levels[i].total_set.freq <= desired_freq)
                  break;
  
          /* If we didn't find a relevant setting, use the lowest. */
          if (i == num_levels)
              i--;
      } else {
          /* If we didn't decrease frequency yet, don't increase it. */
          if (!sc->tz_cooling_updated) {
              sc->tz_cooling_active = FALSE;
              goto out;
          }
  
          /* Use saved cpu frequency as maximum value. */
          if (desired_freq > sc->tz_cooling_saved_freq)
              desired_freq = sc->tz_cooling_saved_freq;
  
          /* Find the closest available frequency, rounding up. */
          for (i = num_levels - 1; i >= 0; i--)
              if (levels[i].total_set.freq >= desired_freq)
                  break;
  
          /* If we didn't find a relevant setting, use the highest. */
          if (i == -1)
              i++;
  
          /* If we're going to the highest frequency, restore the old setting. */
          if (i == 0 || desired_freq == sc->tz_cooling_saved_freq) {
              error = acpi_tz_cpufreq_restore(sc);
              if (error == 0)
                  sc->tz_cooling_active = FALSE;
              goto out;
          }
      }
  
      /* If we are going to a new frequency, activate it. */
      if (levels[i].total_set.freq != freq) {
          ACPI_VPRINT(sc->tz_dev, acpi_device_get_parent_softc(sc->tz_dev),
              "temperature %d.%dC: %screasing clock speed "
              "from %d MHz to %d MHz\n",
              TZ_KELVTOC(sc->tz_temperature),
              (freq > levels[i].total_set.freq) ? "de" : "in",
              freq, levels[i].total_set.freq);
          error = CPUFREQ_SET(dev, &levels[i], CPUFREQ_PRIO_KERN);
          if (error == 0 && !sc->tz_cooling_updated) {
              sc->tz_cooling_saved_freq = freq;
              sc->tz_cooling_updated = TRUE;
          }
      }
  
  out:
      if (levels)
          free(levels, M_TEMP);
      return (error);
  }
  #endif
  
  /*
   * Passive cooling thread; monitors current temperature according to the
   * cooling interval and calculates whether to scale back CPU frequency.
   */
  static void
  acpi_tz_cooling_thread(void *arg)
  {
      struct acpi_tz_softc *sc;
      int perf, curr_temp, prev_temp;
  #ifdef __FreeBSD__
      int error;
  #endif
  
      ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
  
      sc = (struct acpi_tz_softc *)arg;
      get_mplock();
  
      prev_temp = sc->tz_temperature;
      while (sc->tz_cooling_enabled) {
          if (sc->tz_cooling_active)
              (void)acpi_tz_get_temperature(sc);
          curr_temp = sc->tz_temperature;
          if (curr_temp >= sc->tz_zone.psv)
              sc->tz_cooling_active = TRUE;
          if (sc->tz_cooling_active) {
              perf = sc->tz_zone.tc1 * (curr_temp - prev_temp) +
                     sc->tz_zone.tc2 * (curr_temp - sc->tz_zone.psv);
              perf /= 10;
  
              if (perf != 0) {
  #ifdef __FreeBSD__
                  error = acpi_tz_cpufreq_update(sc, perf);
  
                  /*
                   * If error and not simply a higher priority setting was
                   * active, disable cooling.
                   */
                  if (error != 0 && error != EPERM) {
                      device_printf(sc->tz_dev,
                          "failed to set new freq, disabling passive cooling\n");
                      sc->tz_cooling_enabled = FALSE;
                  }
  #endif
              }
          }
          prev_temp = curr_temp;
          tsleep(&sc->tz_cooling_proc, 0, "cooling",
              hz * sc->tz_zone.tsp / 10);
      }
      if (sc->tz_cooling_active) {
  #ifdef __FreeBSD__
          acpi_tz_cpufreq_restore(sc);
  #endif
          sc->tz_cooling_active = FALSE;
      }
      sc->tz_cooling_proc = NULL;
      ACPI_LOCK(thermal);
      sc->tz_cooling_proc_running = FALSE;
      ACPI_UNLOCK(thermal);
      rel_mplock();
  }
  
  /*
   * TODO: We ignore _PSL (list of cooling devices) since cpufreq enumerates
   * all CPUs for us.  However, it's possible in the future _PSL will
   * reference non-CPU devices so we may want to support it then.
   */
  static int
  acpi_tz_cooling_is_available(struct acpi_tz_softc *sc)
  {
      return (sc->tz_zone.tc1 != -1 && sc->tz_zone.tc2 != -1 &&
          sc->tz_zone.tsp != -1 && sc->tz_zone.tsp != 0 &&
          sc->tz_zone.psv != -1);
  }
  
  static int
  acpi_tz_cooling_thread_start(struct acpi_tz_softc *sc)
  {
      int error;
  
      ACPI_LOCK(thermal);
      if (sc->tz_cooling_proc_running) {
          ACPI_UNLOCK(thermal);
          return (0);
      }
      sc->tz_cooling_proc_running = TRUE;
      ACPI_UNLOCK(thermal);
      error = 0;
      if (sc->tz_cooling_proc == NULL) {
          error = kthread_create(acpi_tz_cooling_thread, sc,
              &sc->tz_cooling_proc,
              "acpi_cooling%d", device_get_unit(sc->tz_dev));
          if (error != 0) {
              device_printf(sc->tz_dev, "could not create thread - %d", error);
              ACPI_LOCK(thermal);
              sc->tz_cooling_proc_running = FALSE;
              ACPI_UNLOCK(thermal);
          }
      }
      return (error);
  }

Cache object: 2a839474795f9a062896e14c3db4108b