I am unable to adjust brightness levels through Gnome. I had the same issue with 18.04 but it was resolved there (honestly, I can't remember how).
lspci|grep VGA00:02.0 VGA compatible controller: Intel Corporation Core Processor Integrated Graphics Controller (rev 18)xrandr --output LVDS-1 --brightness 0.95<-- this works through the terminalexcerpt from /etc/default/grubGRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"
Thank you in advance.