kmscon enters zombie state

[syntaxman]

Hello,

I'm running an up-to-date NixOS system. I have installed kmscon and it successfully starts up, replacing the kernel console and agetty. The problem appears if I switch to a VT, but don't do anything to log in. I start in X at tty2, and switch to tty1, where I see kmscon take control of the display and present a login prompt. I create no input at all. If I go back to tty2, then after about a minute, I can check on tty1 again and it will display the error, "Login timed out after 60 seconds". Keyboard input is displayed, but ignored. I am still able to switch to other ttys. The process table will show that kmscon instance is now a zombie. This is 100% predictable on any of the ttys.

This is the relevant part of my configuration.nix:
services.kmscon = {
enable = true;
hwRender = true;
fonts = [ { name = "Inconsolata Nerd Font"; package = pkgs.inconsolata-nerdfont; } ];
extraConfig = ''
font-size=16
font-dpi=255
font-engine=pango
xkb-model=pc105
xkb-layout=us
gpus=all
render-engine=gltex
'';
};

console = {
font = "Lat2-Terminus16";
useXkbConfig = true; # use xkb.options in tty.
earlySetup = true;
};

[jflanglois]

I end up in a similar state, but not the same way: NixOS/nixpkgs#315198