Dell Inspiron 8100 - how to turn off LCD backlight (in console mode)?

I have an old laptop, Dell Inspiron 8100.
It runs FreeBSD, RELENG_6:
root@kg-i82# uname -a
FreeBSD kg-i82.kg4.no 6.3-PRERELEASE FreeBSD 6.3-PRERELEASE #2: Sat Oct 27 02:42:35 CEST 2007 root@xxxxxxxxxxxxx:/usr/obj/usr/src/sys/I81K i386

The machine has a Nvidia gfx card:
root@kg-i82# pciconf -lv | grep -B 4 VGA
acpi_video0@pci1:0:0: class=0x030000 card=0x00e61028 chip=0x011210de rev=0xb2 hdr=0x00
vendor = 'NVIDIA Corporation'
device = 'NV11 GeForce2 Go / MX Ultra'
class = display
subclass = VGA

It is used as a firewall, so it doesn't run Xorg, it only runs in console (text) mode.
I use blank_saver to turn off the screen (text), and this works. I have tested with green_saver as well, and that also works.

The problem is that the LCD backlight stays on. How do I turn it off?
Ideally, the backlight would turn off with the screensaver, and turn on when the screensaver is deactivated again.

I tried with acpi_video, which gives me this:
root@kg-i82# sysctl hw.acpi.video
hw.acpi.video.crt0.active: 0
hw.acpi.video.lcd0.active: 1

I can change hw.acpi.video.lcd0.active to 0 (zero), but the display still stays on.
It doesn't seem like the i8k have a lid switch either:
root@kg-i82# sysctl hw.acpi
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: 1
hw.acpi.verbose: 0
hw.acpi.disable_on_reboot: 0
hw.acpi.handle_reboot: 0
hw.acpi.reset_video: 0
hw.acpi.cpu.cx_lowest: C1
hw.acpi.acline: 1
hw.acpi.battery.life: 91
hw.acpi.battery.time: -1
hw.acpi.battery.state: 2
hw.acpi.battery.units: 2
hw.acpi.battery.info_expire: 5
hw.acpi.thermal.min_runtime: 0
hw.acpi.thermal.polling_rate: 10
hw.acpi.thermal.user_override: 0
hw.acpi.thermal.tz0.temperature: 60.5C
hw.acpi.thermal.tz0.active: -1
hw.acpi.thermal.tz0.passive_cooling: 0
hw.acpi.thermal.tz0.thermal_flags: 0
hw.acpi.thermal.tz0._PSV: -1
hw.acpi.thermal.tz0._HOT: -1
hw.acpi.thermal.tz0._CRT: 101.0C
hw.acpi.thermal.tz0._ACx: -1 -1 -1 -1 -1 -1 -1 -1 -1 -1
hw.acpi.video.crt0.active: 0
hw.acpi.video.lcd0.active: 1

There isn't an acpi_dell or acpi_i8k module, at least I haven't found one.
I have searched quite a bit on Google, but haven't found anything helpful.

Any hints on how to get the backlight to turn off and on again (synced to the console screensaver)?
--
Torfinn Ingolfsen,
Norway
.

Relevant Pages

  • Re: Dell Inspiron 8100 - how to turn off LCD backlight (in console mode)?
    ... Ideally, the backlight would turn off with the screensaver, and turn on when the screensaver is deactivated again. ... IMHO, either of the acpi, apm or sc driver should have taken care of backlight control and, or display power management. ... FYI, though the above looks like a page from FreeBSD 7.0, but I currently am running FreeBSD 8.0-CURRENT on my DELL Inspiron 4150/1.8GHz/256MB/40GB machine. ...
    (comp.unix.bsd.freebsd.misc)
  • Re: New "feature"
    ... I never said I use a screensaver program, I said LCD screens do get 'burned' when there is a constant image. ... It's the LCD pixels that are the issue of course, not the backlight. ... Not really an issue when the machine is idle rather than in sleep. ...
    (comp.sys.mac.system)
  • Re: Windows Mobile 2003 ce "screensaver"
    ... > There is no "screensaver" funktiunallity on a windows mobile, ... > backlight and adjust the "turn off backlight if device not used for" there ... > connected to external power, the last one is on the "external power" tab. ... > you can allso adjust the time for when the device turn off in Start -> ...
    (microsoft.public.pocketpc)