Teach Xrandr to find monitors after reconnecting to the docking station)?

Question

Monitors

Hello gentlemen.
The essence of the problem:
Dell E7240 laptop, monitors are connected via displayport. In the 3.17 kernel, they finally made normal support and now you can connect many monitors to a laptop. But. When "redoking" (essentially turning off monitors - then reconnecting), they refuse to appear in xrandr. Helps restart iksov. So I'm wondering which demon is looking for them and still finds them? I have debian sid. There is no such problem in Ubuntu, that is, this bus is apparently constantly scanned there.