RE: [PATCH v8 3/8] thunderbolt: Communication with the ICM (firmware)

Dell - Internal Use - Confidential  

There is small problem, though. On non-Apple systems the host controller only
appears when something is connected to thunderbolt ports. So the char device
would not be there all the time. However, I think we can still notify the
userspace by sending an extra uevent when we detect there is a PCIe device or
inter-domain connection plugged in.

Why couldn't you just create it the first time a device is plugged into a Thunderbolt
port and leave it until the module is cleaned up?  If the host controller goes to sleep
an event could be sent to the daemon to let it know it disappeared and not to expect
data on the char device for now, but leave the node around.