I have a Samsung laptop r580 with radeon hd 5 series. I installed Manjaro but I can't change the backlight. I installed ati-catalyst drivers. I tried set grub parameters to
acpi_backlight=vendor (it works on Ubuntu) but it doesn't help. I also retried
video, native, none and add
acpi_osi=Linux but it doesn't change all same.
How can I enable the backlight control?
P. S. Fn keys work the backlight indicator shows on the screen but the screen backlight always on maximum and doesn't change.