Serial port access via USB dropping lots of data...

[toptensoftware]

Receiving data from a serial uart device seems to drop lots of data.

• Host: Windows 10 with VirtualBox 6.1 with extension pack
• Guest: Xubuntu 18.04 with guest additions
• FTDI serial USB module connected to USB port and passed through to Xubuntu
• FPGA connected to the FTDI module sending serial data at 115200 baud. The data is sent in 64-byte chunks, one chunk per second (it's a test project and that's just what I've selected for testing).

I'm finding that:

• Xubuntu on a real machine - works fine.
• Xubuntu in a VirtualBox VM - fails.

Under VirtualBox, I get maybe 16 bytes out of every 64 byte chunk and occasional data corruption (as in bytes that I know aren't being transmitted showing up).

The commands I'm using the dump the serial port are:

$ sudo ssty -F /dev/ttyACM1 115200 raw -echo $ sudo xxd /dev/ttyACM1

Attached screen shot shows correct serial dump (under windows), on the right, the messed up data via VirtualBox.

VirtualBox Log also attached

[toptensoftware]

VirtualBox Log File

[toptensoftware]

Screen Shot

[aeichner]

You seem to have the OHCI/EHCI emulation selected which is hard to emulate properly. You could try switching to the XHCI controller for the VM which is much more stable, your guest OS should support it out of the box just fine. We'll see whether we can do anything to improve behavior with the OHCI/EHCI emulation nevertheless but that will take quite some time.

[toptensoftware]

Thanks... you're right, switching to xhci seems to have resolved it.