I have so many questions about this stuff! In particular though - im running a single GPU passthrough setup on my machine. It works smoothly, but I need to shut

I have so many questions about this stuff! In particular though - im running a single GPU passthrough setup on my machine. It works smoothly, but I need to shutdown the display manager (gdm/lightdm etc. depending on distro) before unbinding the graphics card from the host and assigning it to the guest. This means when I get back to my host, i have to relogin and all my windows/apps are gone. There seems to be no way to save/restore the state of X11 (i know apps themselves wouldn't save state). Is there something fundamental about how display managers tie into the GPU that makes it impossible? Is it possible to configure X11 and display managers to use software rendering only?