cdc-wdm: unable to connect after suspend

Hi,

I recently bought a notebook (Fujitsu Lifebook T904) with integrated
3G/4G modem (Sierra Wireless EM7305) thats powered by the cdc-wdm driver.

It works without any problems on a fresh bootup using Networkmanager.

However, after putting the notebook into standby and waking up again,
I'm unable to get a connection (always reproducible, not signal quality
related).

I see the following error messages:


Couldn't reload current power state: Transaction timed out
[/dev/cdc-wdm1] No transaction matched in received message
<warn> (cdc-wdm1) failed to connect modem: Transaction timed out
<info> (cdc-wdm1): device state change: prepare -> failed (reason
'unknown') [40 120 1]
modem_prepare_result: assertion 'state == NM_DEVICE_STATE_PREPARE' failed


It looks like a driver bug for me, like the device not woken up
correctly. I attached the syslog.

I'm running Arch Linux amd64 with an 3.15.0-rc8 kernel, and
NetworkManager 0.9.8.10.

Is there anybody else who observed this behaviour?

Florian