The modernization of PCIe hotplug in Linux

Again, this situation is already (at least partially, IIRC) dealt with in the code base. There are these weird laptops that have a GPU to augment the (much lower performance one) in the laptop; you want to be able to switch back and forth (the high power GPU gets powered down).

I don't remember if all the work has been done in the X server, but certainly the applications and window managers already "do the right thing" for the most part. It gives me great pleasure that I now usually have less trouble handling adding displays/projectors than many/most Windoze users do.

Please don't declare the problem as unsolvable in advance. If it isn't completely solved, it's mostly solved for displays. We started working on these issues with the xrandr extension almost 20 years ago (which keeps getting augmented with time: thanks keithp!). The fundamental shift architecturally happened there, with applications no longer able to presume their root window was immutable.
- Jim