Comment 25 for bug 1905591

Just to add to the report by @manzood, this bug affects my variant of y540 as well.
My complete laptop spec is as follows:
Lenovo Legion Y540
NVIDIA GTX 2060 Mobile
Ubuntu 18.04
kernel 5.4.0-72-generic

and again, the workaround suggested by @sureshot16 does not work, editing /sys/class/backlight/acpi_video0/brightness does not work(except when prime-select is set to intel),
adding 'Option "RegistryDwords" "EnableBrightnessControl=1"' to /usr/share/X11/xorg.conf.d/10-nvidia-brightness.conf does not work neither does adding kernel parameters in grub config.

This brightness issue has been a thorn in my side for the better part of a year, the only version which works is the Nouveau display driver installed via "Software & Updates" but has no CUDA support or Steam integration so that's a deal breaker for me.

Unlike @manzood, suspending the laptop and resuming has never worked for me and causes artifacts and flickering in 460 specifically. Issue persists in 465 as well.