How to change brightness with Fn key?

pRags · Jun 14, 2015

Just installed FreeBSD 10.1, with GNOME 3 on a Sony Vaio laptop.

Everything works fine, including being able to control the volume with Fn + (F3 or F4). However, the Fn + (F5 or F6) key combinations do not change the brightness.

When trying to change brightness by the command line, with xbacklight, I always get the error "no outputs have backlight property".

tobik@ · Jun 14, 2015

Load acpi_video(4) ( kldload acpi_video). If it works, run sysrc kld_list+=acpi_video to automatically load the module on boot.

pRags · Jun 14, 2015

Thanks. I've tried your suggestion, and now, when I try to use xbacklight, I do not get an error, but the backlight does not change. The keys still do nothing.

ondra_knezour · Jun 14, 2015

See also acpi_sony(4)

pRags · Jun 14, 2015

ondra_knezour said:
See also acpi_sony(4)

Thanks. I've added the following to /boot/loader.conf:

Code:

acpi_sony_load="YES"

But after a restart, I am still unable to change the brightness.

ondra_knezour · Jun 14, 2015

Try to play with the value of the dev.acpi_sony.0.brightness sysctl to see if it is even working. It is also possible, that you would need some utility like deskutils/tpb for IBM ThinkPads to hook onto buttons.

pRags · Jun 15, 2015

ondra_knezour said:
Try to play with the value of the dev.acpi_sony.0.brightness sysctl to see if it is even working. It is also possible, that you would need some utility like deskutils/tpb for IBM ThinkPads to hook onto buttons.

Sorry, I am not familiar with that command. Could you please tell me exactly what to enter into the terminal to change the brightness?

ondra_knezour · Jun 15, 2015

See sysctl(8) manpage.

Something like sysctl dev.acpi_sony.0.brightness=number may work.

pRags · Jun 15, 2015

ondra_knezour said:
See sysctl(8) manpage.

Something like sysctl dev.acpi_sony.0.brightness=number may work.

Thanks, this is the output of the command:

Code:

root@Chris:/usr/home/Chris # sysctl dev.acpi_sony.0.brightness=4
dev.acpi_sony.0.brightness: 8 -> 8

And the brightness is not changed.

decreo · Nov 12, 2019

tobik@ said:
Load acpi_video(4) ( kldload acpi_video). If it works, run sysrc kld_list+=acpi_video to automatically load the module on boot.

Works perfect for Panasonic CF-54 (GPU HD Graphics 620) with FreeBSD 12.0-RELEASE, thanks a lot.