platforms/drm: work around dpms problems
Some monitors (for example, all DisplayPort monitors) will trigger a hotplug event when they go to sleep, which causes all the monitors to wake up again and mess up our display configuration. Instead of having that happen, wait for processing hotplug events until the user explicitly wakes up the session again.
Should probably also be linked here: https://gitlab.freedesktop.org/drm/amd/-/issues/662. For some monitors there is no proper kernel level solution possible, or at least not in sight