pvrinput uses udev-interface of dynamite
Plug in you pvrusb2 and it will be used by vdr!
dynamite now offers a service-interface for adding udev-filters to "add"-actions. If you plug in a pvrusb2 udev will generate an event in the video4linux-subsystem with the devicepath the driver created.
pvrinput just has to call the dynamite-service in its initialization:
AddUdevMonitor video4linux /dev/video
If the udev-monitor of dynamite grabs an event of the subsystem "video4linux" whose devnode starts with "/dev/video" it tries to attach this device by calling all "cDynamicDeviceProbe"s. And since pvrinput has registered a handler it will create a cPvrDevice for this video-device. Voilà!
What I have to test now is what happens if an ivtv-device is added - there would be more than one /dev/video and only the first should be used. I think, cPvrDevice::Probe should only react on device-numbers less than 16, what do you think?