Only showing a machine, installed 430 drivers,
Under the/sys/class/backlight is empty,
Try the following steps, without success,

1. Inside the/etc/default/grub modified the line GRUB_CMDLINE_LINUX_DEFAULT as follows:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"
Executed: sudo update - grub and rebooted

2. Created a file/etc/modprobe. D/99 - nvidia - backlight. Conf
Put: options nvidia NVreg_EnableBacklightHandler=1
Inside the file and
Executed: sudo update - initramfs -u

3. Created a file/usr/share/X11/xorg conf. D/12 - nvidia. Conf
Put the following in the file:

Section "OutputClass
"Identifier "nvidia
"MatchDriver "nvidia - DRM"
Driver "nvidia
"The Option "AllowEmptyInitialConfiguration
"The Option "RegistryDwords" "EnableBrightnessControl=1;"
ModulePath "/usr/lib/x86_64 - - the gnu/Linux nvidia/xorg"
EndSection

Rebooted

Using the command sudo setpci -s 1 c: 00.0 the F4. B=FF adjust brightness also have no reaction,
1 c: 00.0 VGA compatible controller: NVIDIA Corporation Device 1 f02 (rev a1)

How can help adjust the display brightness?