On Tue, 2018-01-23 at 14:02 +0000, Foxtrot Mike via arch-general wrote: > Hi all, > > With my AMD card, I was able to set my monitor's (ViewSonic VA2249, > connected via DVI) brightness and contrast from command line using: > > ddcutil --display 1 setvcp 12 20 > > Later on, I swapped AMD card with an NVIDIA one (using nvidia 387.34- > 20). I tried using ddcutil with this new card as well, but I got this > error: > > ~$ sudo ddcutil detect > Failure getting EDID for /dev/i2c-5: status code=DDCRC_EDID(-3016): > invalid EDID > No displays found > ~$ > > I tried googling this error, but didn't find anything helpful. > > So I tried using xbacklight instead. It didn't give any positive > results either, even when I provided different kernel paramters as > discribed in [1]. No matter what I do with acpi and kernel > parameters, "/sys/class/backlight/acpi_video0/brightness" doesn't > give actual values. Also, 'xbacklight set' has no effect on screen > brightness at all. > > I also tried adding `Option "RegistryDwords" > "EnableBrightnessControl=1"` in "/usr/share/X11/xorg.conf.d/10- > nvidia-drm-outputclass.conf". Still keyboard brigthness keys couldn't > change the brightness. > > Can someone help me get ddcutil working with nvidia proprietary > driver? > > Regards. > > [1] https://wiki.archlinux.org/index.php/Backlight#Kernel_command-lin > e_options Never used ddcutil. Have a look at xrandr --brightness. Works perfectly for me on my OLED without backlight functionality. The following example gives u 30% brightness: xrandr --output DVI-0 --brightness 0.3 I think xrandr works on Wayland, although I cant currently test it. It works on my NVidia / LCD setup. Although on this setup it makes less sense: the actual backlight stays at 100%, just the colors are adjusted. On an OLED without backlight the solution works 100% smooth. Check the wiki pages on HP x360 laptop [1]. There is also a script available linking /sys/class/backlight/intel_backlight to xrandr brightness in case you have brightness hardware keys. regards, ente [1] https://wiki.archlinux.org/index.php/HP_Spectre_x360_13-4231ng
