When is cdc-wdm0 ready?

[Tom Isaacson]

I'm having a problem in my app right now where I wait for
/dev/cdc-wdm0 to appear then call:
    qmicli --device=/dev/cdc-wdm0 --device-open-qmi --dms-get-ids
but it fails with:
    error: couldn't create client for the 'dms' service: CID
allocation failed in the CTL client: Transaction timed out
If I add a delay it works fine.

Is there some way of checking if cdc-wdm0 is ready to receive commands?

Thanks.

Tom Isaacson