Mbox Meson Ref ((link)) <PC>

: It acts as a fallback label in the device tree or kernel configuration that identifies the HDMI source to other CEC-enabled devices. 3. Troubleshooting and Customization

You wrote \mbox$meson$ ref . This is redundant and can cause spacing issues. Fix: Either use math mode outside or use \text{} from amsmath . mbox meson ref

But you get an error because \ref outputs numbers, which are fine in math mode, but the space or the text "meson ref." is not. The correct way is: : It acts as a fallback label in

The name given to the kernel and device tree structure for Amlogic's multimedia processors. which are fine in math mode