Laptop lid switch and ACPI

Norberto Meijome freebsd at
Tue Mar 6 13:50:31 UTC 2007

On Mon, 5 Mar 2007 16:28:06 -0500
frzburn <frzburn at> wrote:

> I need a hint on how to get my screen turn off (backlight too) on my Dell
> Laptop.
> I have an Inspiron 6400 (e1505), and FreeBSD 6 - amd64.

Hi there,
I am not sure how to switch off the screen on the dell (independent of
ACPI)... in all laptops I've seen, it's fully controlled by the hardware
Have you got acpi working ? 

If you *do* have ACPI working, and you want to see whether it is firing acpi at
all when you close the lid, you can restart devd in debugging mode:

/etc/rc.d/devd stop
devd -dD

and then try your ACPI events.

Also, you should be able to tell your ACPI module to let you handle the events
manually. For example, with the acpi_ibm.ko, the knob = 1

tells acpi to pass all acpi messages to devd for handling. Search the logs (in
mobile@ , i believe) - i've posted my config for some sample actions on
different ACPI events.

BTW, you may be able to switch off the display using a user mode application
that is related to your video card. For example, if you have a Radeon card, the
radeontool allows you to switch off the panel and external monitor outputs
(although the ext monitor gets switched on when you switch to X's VT)

{Beto|Norberto|Numard} Meijome

"Against logic there is no armor like ignorance."
  Laurence J. Peter

I speak for myself, not my employer. Contents may be hot. Slippery when wet.
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