[PVE-User] USB passthrouh with kernel 4.4.x

Wolfgang Bumiller w.bumiller at proxmox.com
Wed May 11 10:35:58 CEST 2016

On Mon, May 09, 2016 at 12:21:05PM +0200, Eneko Lacunza wrote:
> Hi all,
> We're trying to migrate a Windows server 2000 VMs, from a PVE 3.2 host with
> kernel 2.6.32-28-pve to PVE 4.2 with kernel 4.4.6-1-pve .
> This VM has a USB passtrough devide, a GSM modem:
> Bus 003 Device 030: ID 1410:5010 Novatel Wireless
> Sometimes it appears as 1410:4400 not 1410:5010 :) Don't know why is it
> doing this funny ID changing.

Sounds like a usb_modeswitch thing. Many USB modems can appear as either
storage or modem with a command to make them switch, which also changes
their USB id. See if you have the usb-modeswitch / usb-modeswitch-data
packages installed. It comes with udev rules to automatically trigger
when the device is plugged in - if this behavior is enabled then you
should see it as one device first, and as the other device after a few
seconds. Perhaps host and guest are fighting over this? If you don't
need it you could probably remove it on the host, then the guest VM
would be responsible for making it switch between storage and modem

> 4.4 kernel is loading usb_storage and uas drivers for this, but it is a GSM
> modem.
> Passtrough in PVE 3.2 works perfectly.
> In PVE 4.4 is not reliable; sometimes VM doesn't see the device, sometimes
> it does see it, but doesn't appear to work almost all the time (it is used
> to send SMS), although sometimes it does send SMSs. This doesn't really seem
> a coverage problem, device led is showing data conection.
> Any advice regarding this? We have others VMs on this node already, so
> trying different kernels is not an easy option...

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