acpi laptop fan control

[epilogue]

hello all,

i'm hoping that someone here might have a suggestion for a longstanding
and nagging little problem - my laptop fan /never/ shuts off.

the machine is a Compal N30W, which is the OEM version of the Dell
Inspiron 5000.  i'm running 5.3 and have the latest BIOS.

from what i've read, it is supposed to be a green fan, which means that
it should adapt to the temperature of the machine.  off when not needed
and up through various speeds when required.  i've noted at least two
settings: 1. low, the constant (and irritating) whir and 2. high, when
the temperature jumps during heavy use.

i tried force a state change with sysctl, but as you can see, the change
is denied:

# sysctl hw.acpi.thermal.tz0.active=0
hw.acpi.thermal.tz0.active: -1 -> -1

# sysctl hw.acpi.thermal.tz0.active=1
hw.acpi.thermal.tz0.active: -1 -> -1

have also tried forcing a change through sysctl.conf (and loader.conf)
then a reboot, but neither manages to change the state from -1.

these are new features and the man pages only have so much to offer. 
hopefully, someone will have a suggestion.

thanks for your time.


cheers,
epi

----------------------------------
> sysctl -a | grep -i acpi
----------------------------------

  acpibatt     2     1K      1K        2  16
      acpidev    59     2K      2K       59  32
      acpisem    18     2K      2K       18  64
     acpitask     0     0K      1K    64938  16,32
       acpica  1635    87K     91K   904153 
16,32,64,128,256,512,1024,2048 kern.timecounter.hardware: ACPI-safe
kern.timecounter.choice: TSC(800) ACPI-safe(1000) i8254(0)
dummy(-1000000) debug.acpi.acpi_ca_version: 0x20040527
debug.acpi.semaphore_debug: 0
hw.acpi.supported_sleep_state: S1 S3 S4 S5
hw.acpi.power_button_state: S5
hw.acpi.sleep_button_state: S1
hw.acpi.lid_switch_state: NONE
hw.acpi.standby_state: S1
hw.acpi.suspend_state: S3
hw.acpi.sleep_delay: 1
hw.acpi.s4bios: 0
hw.acpi.verbose: 1
hw.acpi.reset_video: 1
hw.acpi.cpu.throttle_max: 8
hw.acpi.cpu.throttle_state: 8
hw.acpi.cpu.cx_supported: C1/0 C2/10
hw.acpi.cpu.cx_lowest: C2
hw.acpi.cpu.cx_usage: 0.22% 99.77%
hw.acpi.thermal.min_runtime: 0
hw.acpi.thermal.polling_rate: 10
hw.acpi.thermal.tz0.temperature: 3330
hw.acpi.thermal.tz0.active: -1
hw.acpi.thermal.tz0.thermal_flags: 0
hw.acpi.thermal.tz0._PSV: 3590
hw.acpi.thermal.tz0._HOT: -1
hw.acpi.thermal.tz0._CRT: 3880
hw.acpi.thermal.tz0._ACx: 3530 3470 -1 -1 -1 -1 -1 -1 -1 -1
hw.acpi.battery.life: 100
hw.acpi.battery.time: -1
hw.acpi.battery.state: 0
hw.acpi.battery.units: 2
hw.acpi.battery.info_expire: 5
hw.acpi.acline: 1
machdep.acpi_timer_freq: 3579545
machdep.acpi_root: 1012160
dev.acpi.0.%desc: COMPAL N30W   
dev.acpi.0.%driver: acpi
dev.acpi_sysresource.0.%desc: System Resource
dev.acpi_sysresource.0.%driver: acpi_sysresource
dev.acpi_sysresource.0.%location: handle=\_SB_.MEM_
dev.acpi_sysresource.0.%pnpinfo: _HID=PNP0C01 _UID=0
dev.acpi_sysresource.0.%parent: acpi0
dev.acpi_sysresource.1.%desc: System Resource
dev.acpi_sysresource.1.%driver: acpi_sysresource
dev.acpi_sysresource.1.%location: handle=\_SB_.PCI0.PX40.MOTH
dev.acpi_sysresource.1.%pnpinfo: _HID=PNP0C02 _UID=0
dev.acpi_sysresource.1.%parent: acpi0
dev.acpi_ec.0.%desc: Embedded Controller: GPE 0x9
dev.acpi_ec.0.%driver: acpi_ec
dev.acpi_ec.0.%location: handle=\_SB_.PCI0.PX40.EC0_
dev.acpi_ec.0.%pnpinfo: _HID=PNP0C09 _UID=0
dev.acpi_ec.0.%parent: acpi0
dev.acpi_timer.0.%desc: 24-bit timer at 3.579545MHz
dev.acpi_timer.0.%driver: acpi_timer
dev.acpi_timer.0.%location: unknown
dev.acpi_timer.0.%pnpinfo: unknown
dev.acpi_timer.0.%parent: acpi0
dev.cpu.0.%desc: ACPI CPU (3 Cx states)
dev.cpu.0.%parent: acpi0
dev.acpi_tz.0.%desc: Thermal Zone
dev.acpi_tz.0.%driver: acpi_tz
dev.acpi_tz.0.%location: handle=\_TZ_.THRM
dev.acpi_tz.0.%pnpinfo: _HID=none _UID=0
dev.acpi_tz.0.%parent: acpi0
dev.acpi_lid.0.%desc: Control Method Lid Switch
dev.acpi_lid.0.%driver: acpi_lid
dev.acpi_lid.0.%location: handle=\_SB_.LID_
dev.acpi_lid.0.%pnpinfo: _HID=PNP0C0D _UID=0
dev.acpi_lid.0.%parent: acpi0
dev.acpi_lid.0.wake: 1
dev.acpi_cmbat.0.%desc: Control Method Battery
dev.acpi_cmbat.0.%driver: acpi_cmbat
dev.acpi_cmbat.0.%location: handle=\_SB_.BAT0
dev.acpi_cmbat.0.%pnpinfo: _HID=PNP0C0A _UID=1
dev.acpi_cmbat.0.%parent: acpi0
dev.acpi_cmbat.1.%desc: Control Method Battery
dev.acpi_cmbat.1.%driver: acpi_cmbat
dev.acpi_cmbat.1.%location: handle=\_SB_.BAT1
dev.acpi_cmbat.1.%pnpinfo: _HID=PNP0C0A _UID=2
dev.acpi_cmbat.1.%parent: acpi0
dev.acpi_acad.0.%desc: AC Adapter
dev.acpi_acad.0.%driver: acpi_acad
dev.acpi_acad.0.%location: handle=\_SB_.AC__
dev.acpi_acad.0.%pnpinfo: _HID=ACPI0003 _UID=0
dev.acpi_acad.0.%parent: acpi0
dev.pcib.0.%desc: ACPI Host-PCI bridge
dev.pcib.0.%parent: acpi0
dev.pcib.1.%desc: ACPI PCI-PCI bridge
dev.pci.0.%desc: ACPI PCI bus
dev.pci.1.%desc: ACPI PCI bus
dev.acpi_button.0.%desc: Power Button
dev.acpi_button.0.%driver: acpi_button
dev.acpi_button.0.%location: handle=\_SB_.PWRB
dev.acpi_button.0.%pnpinfo: _HID=PNP0C0C _UID=0
dev.acpi_button.0.%parent: acpi0
dev.acpi_button.0.wake: 1
dev.acpi_button.1.%desc: Sleep Button
dev.acpi_button.1.%driver: acpi_button
dev.acpi_button.1.%location: handle=\_SB_.SBTN
dev.acpi_button.1.%pnpinfo: _HID=PNP0C0E _UID=0
dev.acpi_button.1.%parent: acpi0
dev.atdma.0.%parent: acpi0
dev.attimer.0.%parent: acpi0
dev.attimer.1.%parent: acpi0
dev.atpic.0.%parent: acpi0
dev.npxisa.0.%parent: acpi0
dev.atkbdc.0.%parent: acpi0
dev.psmcpnp.0.%parent: acpi0
dev.fdc.0.%parent: acpi0
dev.ppc.0.%parent: acpi0
dev.sio.0.%parent: acpi0
dev.sio.1.%parent: acpi0