Is there a client API available to check if a device is connected to a USB hub that supports power cycling?

Submitted by apchandr on #1

Hi Michael,

Is there a client API available to determine if a USB device is connected to a hub like "VirtualHere USB 3 4-Port Hub" that supports the `power_cycle_port` feature? It seems that using the command `CUSTOM EVENT,<address>,power_cycle_port` returns an 'OK' status even when the device is not connected to a hub or the hub does not support this feature instead of indicating a failure.

I've also observed that executing `power_cycle_port` via the client API from any client machine disconnects the device from other clients (i.e., device in-use somewhere) and terminates other user's connection similar to the `STOP USING` command in admin mode as described here( https://www.virtualhere.com/comment/1314#comment-1314 ). Any thoughts?

 

Submitted by Michael on Fri, 2025/04/11 - 06:39

#2

You need to use https://github.com/mvp/uhubctl if you don't know and need to query that information.

VirtualHere will try to issue a power cycle command to the hub regardless, but if the hub attached doesn't support PPPS then it will be ignored by the hub. 

VirtualHere USB Hubs always fully support PPPS (Per port Power Switching)

If you power cycle the port - its just like you physically unplugged the device from the port then put it back in a few seconds later. So any client that was connected to that device would be disconnected because its powered off - the device is gone.

It would come back on a few seconds later and then they can reconnect. You could set "Auto-Use Device" from the client and that client would automatically use the device when it comes back online again.