View Full Version : ATI HD2400 Screen brightness control
06-13-2010, 12:21 PM
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)
ATI mobility radeon HD2400 256MB RAM
06-14-2010, 03:17 PM
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:
There are a variety of different acpi modules you can try loading based
upon your system type:
# ls /boot/kernel/acpi*
I'm thinking acpi_video may be your winner though, take a look at the
man page for it for more details.
07-18-2010, 03:38 PM
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?
07-18-2010, 08:40 PM
Add acpi_video="Yes" to /boot/loader.conf
07-18-2010, 09:58 PM
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
07-19-2010, 12:14 AM
Yes, my mistake. You need _load.
07-22-2010, 04:45 PM
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.
Just finished installing 8.1 and I'm glad to let you know the fix holds up.
03-07-2011, 10:50 AM
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.
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