Thank you both. I'm glad it is not a mistake I did. I would like to fix the GDM bug(s) but right now I do not know scheme nor do I know much about how GDM, X, and Wayland work. I am learning scheme from this book though. https://mitpress.mit.edu/sites/default/files/sicp/index.html 
 
On Sun, Dec 16, 2018, at 5:05 AM, Chris Marusich wrote: 
> Hi Peter and Timothy, 
>  
> Timothy Sample <samplet@ngyro.com> writes: 
>  
> > [...] If I want to lock and suspend, I use the following rather 
> > unglamorous command: 
> > 
> > $ xlock & (sleep 3; loginctl suspend) 
> > 
> > If anyone has any better advice, I would love to hear it! 
>  
> I do something similar, but with xscreensaver. I set it up so that my 
> screen automatically locks after a period of no activity, and also so 
> that I can manually lock it on demand. Here's how I do it. 
>  
> First, in my OS configuration file, I replace all screen lockers in 
> %desktop-services with a screen locker service that uses xscreensaver: 
>  
>  (services (cons* 
>  (screen-locker-service xscreensaver) 
>  (remove-screen-lockers %desktop-services))) 
>  
> The procedure remove-screen-lockers is a custom procedure I've defined 
> in my OS config file. Here it is: 
>  
>  (define (remove-services kind-to-remove) 
>  "Return a procedure that accepts a single argument (a list of 
>  <service> objects) and returns a new list that contains the same 
>  elements, but with the specified kind-to-remove removed." 
>  (lambda (services) 
>  (remove (match-lambda 
>  ((? service? s) 
>  (eq? kind-to-remove (service-kind s)))) 
>  services))) 
>  
>  (define remove-screen-lockers 
>  (remove-services 'screen-locker)) 
>  
> You don't have to remove all the other screen lockers, but I didn't need 
> them, so I decided to remove them. 
>  
> This installs specifically the "xscreensaver" program as a setuid-root 
> program. This makes it possible to manually start the xscreensaver 
> program and to configure it (both via the "xscreensaver" program). 
>  
> Because I also want to be able to manually lock the screen on demand 
> (via the separate "xscreensaver-command" program), I also install the 
> xscreensaver package to my system profile by adding it to the "packages" 
> field of my OS declaration. You probably don't want to add it to your 
> user profile, since if you do that, your user profile's "xscreensaver" 
> program (which is not setuid-root) will take precedence (via the PATH 
> environment variable) over the setuid-root "xscreensaver" program 
> installed in /run/setuid-programs. Although it's technically possible 
> for xscreensaver to function correctly without being setuid root [1], I 
> haven't figured out how to do it on GuixSD at this time. 
>  
> Once the xscreensaver package is installed, I create an alias in my 
> ~/.bashrc that enables me to lock the screen on demand after 
> xscreensaver has been started. 
>  
>  alias lk='xscreensaver-command -activate' 
>  
> Finally, to start xscreensaver automatically when I log into a desktop 
> session, I create an autostart file [2] named 
> ~/.config/autostart/xscreensaver.desktop with the following contents: 
>  
>  [Desktop Entry] 
>  Version=1.0 
>  Type=Application 
>  Name=XScreenSaver 
>  Comment=Launch XScreenSaver 
>  Exec=xscreensaver -nosplash 
>  StartupNotify=false 
>  Terminal=false 
>  Hidden=false 
>  
> Reconfigure your system and reboot to verify that it still boots. To 
> lock the screen while logged into GNOME or similar, just open a terminal 
> (e.g., GNOME Terminal) and run lk. You can also configure xscreensaver 
> by running xscreensaver-prefs. From there, you can configure 
> xscreenlocker to lock the screen after a certain period of idle time. 
>  
> Anyway, I hope that helps! 
>  
> Footnotes:  
> [1] https://www.jwz.org/xscreensaver/faq.html#setuid 
>  
> [2] https://specifications.freedesktop.org/autostart-spec/0.5/ 
>  
> --  
> Chris 
>