Problems if USB-Serial adapter on host was removed during a session.

[ziotibia81]

Scenario:

Guest system have to interact with a device connected to an USB to RS232 adapter.

Guest OS don't have driver for this adapter. Host OS (Linux) have this driver working fine.

On host was created an udev rule to ensure that the specific adapter always have a symlink with the same name (/dev/ttyUSB.TK):

KERNEL=="ttyUSB[0-9]*", DEVPATH=="/devices/pci0000:00/0000:00:1d.1/usb3/3-2/3-2:1.0/ttyUSB[0-9]*", SYMLINK+="ttyUSB.TK"

VM have thins conf:

 <UART>
        <Port slot="0" enabled="true" IOBase="0x3f8" IRQ="4" path="/dev/ttyUSB.TK" hostMode="HostDevice"/>
      </UART>

Guest use his "hardware" serial device.

So now I attach serial adapter, start virtual machine and all works fine.

If the serial adapter is disconnected and reconnected while VM still running on VBox.log I see:

02:41:55.101588 VM: Raising runtime error 'DrvHostSerialFail' (fFlags=0x0)
02:41:55.101633 Console: VM runtime error: fatal=false, errorID=DrvHostSerialFail message="Ioctl failed for serial host device '/dev/ttyUSB.TK' (VERR_DEV_IO_ERROR). The device will not work properly"
02:41:55.102740 HostSerial#0: Serial Write failed with VERR_DEV_IO_ERROR; terminating send thread
02:41:55.102759 PDMThread: Thread 'SerSend' (00007f76e8461d50) quit unexpectedly with rc=VERR_DEV_IO_ERROR.

and serial port on Guest stop to work. Now I have to Shutdown Guest (no reboot) and restart it.

Summarizing: at the first I/O error on device VBox "disconnect" virtual device, closer real device and ignore it during all the session.

I think that would be better if VBox trying to reopen real device, every X seconds, and restore functionality of virtualized device.

[ziotibia81]

Session Log

[aeichner]

Please reopen if still relevant with a recent VirtualBox release.