ATI HD2400 Screen brightness control

[Sander M]

Hi everybody.

As a new PC-BSD user I need a little bit of help.
After succesfully installing PC-BSD 8.0 in triple boot I had to choose my graphic driver. The Vesa driver would not let me use the native resolution of 1280x800. After changing that to the ATI driver I could run the preferred resolution.
But with this driver I cannot change my screen brightness with the 'fn' +F8, F9 keys. Same issue with ATI radeon driver. This function worked with the Vesa driver.

I cannot find a widget to adjust brightness trough the GUI, is there any?

My specs are:
Intel core 2 duo 1.83 ghz (T5550)
3GB RAM
ATI mobility radeon HD2400 256MB RAM

[kmoore134]

I think sometimes you need to load a specific acpi kernel module for
your system to enable the 'Func' keys properly. However you may be able
to manually set the brightness as well. I did some googling and found
some other people with similar issues:

http://forums.freebsd.org/showthread.php?t=9463 ('http://forums.freebsd.org/showthread.php?t=9463')

There are a variety of different acpi modules you can try loading based
upon your system type:

# ls /boot/kernel/acpi*

/boot/kernel/acpi_aiboost.ko
/boot/kernel/acpi_asus.ko
/boot/kernel/acpi_dock.ko
/boot/kernel/acpi_fujitsu.ko
/boot/kernel/acpi_hp.ko
/boot/kernel/acpi_ibm.ko
/boot/kernel/acpi_panasonic.ko
/boot/kernel/acpi_sony.ko
/boot/kernel/acpi_toshiba.ko
/boot/kernel/acpi_video.ko
/boot/kernel/acpi_wmi.ko

I'm thinking acpi_video may be your winner though, take a look at the
man page for it for more details.

[Sander M]

A little late but I tried and my issue is fixed, after typing # kldload acpi_video as root in the terminal my fn keys magically started working :cool:

Thanks a bunch, now I can really start exploring this OS.
How can I setup this kernel module to automatically be loaded at boottime?

[Fatmice]

Add acpi_video="Yes" to /boot/loader.conf

[Sander M]

Ok I added that code and it did not load, however looking at the other entries I figured the line also needed the _load suffix and now I don't have to manually load it afterwards. Thanks!

# Load acpi_video for brightness control
acpi_video_load="YES"

[Fatmice]

Yes, my mistake. You need _load.

[Sander M]

Btw, this fix with acpi_video worked in 8.1 RC1.
I re-installed 8.0 yesterday and then it doesn't work.
Just noticed 8.1 got released, I am prepping my USB stick with it and let you know if this fix holds up.

**EDIT*
Just finished installing 8.1 and I'm glad to let you know the fix holds up.

[Sander M]

For anyone else with this issue: I just installed v8.2 and this issue is still there. But the good news is this fix still holds up.