Can't change screen brightness after update

Hello. I have a laptop with only Nvidia graphics, and after I’ve installed the system I could change the screen brightness. However, after running pacman -Syyu and rebooting, brightness slider does nothing. What can I downgrade to make it work again?

Welcome here, @btwiusearch23,

please share some info about your system by posting output of

inxi -Fazy

Have you tried

acpi_backlight=vendor

as kernel parameter in /etc/default/grub already?

Or some of the variations?

Otherwise, look here.