Keyboard unresponsive when using root or when user is in the 'input' group.

I originally posted this issue on the RetroArch github page but, upon testing the PPA release, discovered it is unique to this release.

I wanted to use RetroArch in KMS mode to use DOSBox as, though game focus mode does exist, it doesn't stop my cinnamon desktop from activating keyboard shortcuts. This lead to me trying the 'udev' input driver, which didn't respond because I didn't have the right permissions. Upon adding my user to the 'input' group, or using root, my keyboard stops responding, even when using the 'x' driver, and my laptop touchpad allows me to navigate retroarch, almost like an analog stick. Not well enough for me to actually control it, though.

I also get this error: "100%: AlpsPS/2 ALPS GlidePoint (2/8) not configured."

To clarify, this happens only when using root or when my user is in the input group, regardless of input driver, and is unique to the flatpak release. Any thoughts?

Reproduce the problem in the RetroArch Flatpak release using KMS with the udev and x input drivers, both as root and with the user in the input group. Check the reported AlpsPS/2 ALPS GlidePoint error and compare keyboard and touchpad behavior. Done means keyboard input works without the touchpad being treated as an analog stick in the affected configurations.

Written by the indexing model from the issue text.