Re: [Qemu-devel] [Bug 319014] Re: serial usb-device can't be passed-through to a guest

[David S. Ahern]

On 06/03/10 09:41, Nico Prenzel wrote:
> Hello Anthony,
> 
> which qemu-kvm version do you expect to work with serial usb devices?
> 
> After you've changed this ticket status and I've checked it again with 
> qemu-kvm version 0.12.4. The reported error message is gone away and the 
> device is present in the guest. The cdc_acm driver loads too without any 
> visible problems, but the device is still unusable.
> The device data led flash if it gets un/initialized by minicom.
> But if I try to make a test dial, nothing happens after I call a phone number.
> 
> To be more precise:
> -host dosn't have loaded the cdc_acm driver
> -guest loads the cdc_acm driver
> -a dial with minicom to the same phone number works on the host, if I load 
> the cdc_acm within the host
> 
> I would like to get this fixed, as I really want to use this usb-device
> as my dusty fax again.
> 

One option I resorted to is using Qemu's emulated USB serial device and
connecting it to the USB serial device host side. The stack then looks like:

  .---------------------.
  | VM                  |
  |                     |
  |    /dev/ttyUSB0     |
  |---------------------|
  | Qemu - serial device|
  '---------------------'
             |
  .---------------------.
  | Host: /dev/ttyUSB0  |
  '---------------------'
            |
  .---------------------.
  |  USB serial port    |++++++++<-- character stream -->++++++++
  '---------------------'


A hack, but it works. :-)

David