Intel Graphics driver for Linux limits the minimum value of brightness you can set. Thanks to the nature of Linux, you can give a middle finger to that policy.

For some reason, the minimum value of brightness I can set on my laptop's screen hurts my eye since I stare at it for longer duration. With this patch you can rebuild the kernel to get a new kernel module parameter. Keep in mind, that patch is for Kernel version 4.18. If you run modinfo i915 after booting with your new patched kernel, you will have this extra :

parm:           disable_arbitrary_minimum_brightness:Disable arbitrary override on minimum brightness value.  (-1=override active [default], 0=zero minimum brightness, 1=use minimum value from vbt) (int)

To be able to set any arbitrary value for your minimum brightness, create a file /etc/modprobe.d/i915.conf and put options i915 disable_arbitrary_minimum_brightness=0 in it.

Restart, and profit. You've given middle finger to Intel. Although nowhere close to what Linus gave to Nvidia, it is somewhat satisfying to me. How about you ?