HOWTO enable 10-bit color on Linux
Modern monitors and AMD graphics cards support 10-bit color. It's not enabled by default on GNU/Linux distributions. Enabling it is just a matter of having one line with
"DefaultDepth 10" in a configuration file in
However, there is one reason you may not want to do this,
Chromium can't into 10-bit color
Every single piece of software you're using will probably work just fine in a 10-bit X environment except for chromium (or chrome). That browser, for whatever reason, can't into 10-bit. It simply does not work. Here is a screenshot with Firefox on the left and Chromium on the right, both showing www.gnu.org:
You may or may not notice that there is a small problem with using Chromium version 73 (and all earlier versions) in X using 10-bit color-depth. If you never use Chromium or Chrome ever then 10-bit is a viable option: It appears to be all alone in it's failure to get into 10-bit.
Example configuration file
/etc/X11/xorg.conf.d/20-amdgpu.conf with the following content will give you 10-bit color:
Section "Screen" Identifier "Default Screen" Monitor "Configured Monitor" Device "Configured Video Device" # 24 for 8-bit or 30 for 10-bit DefaultDepth 30 EndSection
And that's it.
DefaultDepth 30 is the crucial line.