I have a serial port connected device that only works in windows xp and i just can't get it going in my windows vm with ubuntu 9.04 host. The windows program gives the error: Error Opening Port

I have serial port settings as such in virtualbox:

enable serial port checked
port number com 1, irq 4, i/o port 0x3f8
port mode: host device
port/file path: /dev/ttyS0


Here's what i get from dmesg:

dmesg | grep tty
[ 0.004000] console [tty0] enabled
[ 2.004401] serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
[ 2.004825] 00:07: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A



What am i doing wrong? Any help is greatly appreciated.

I have the exact same problem. Extra details:

* Host:
|-- Ubuntu 9.04, all packages updated to latest
|-- Core 2 Duo E8400 @ 3GHz
|-- dmesg | grep tty exactly as above (apart from timings in square brackets)
|-- VirtualBox is version 3.0.4r50677
`-- /dev/ttyS0 is mode 0777

* Guest:
|-- XP Professional Version 2002 Service Pack 2
|-- 828MB RAM
`-- Guest Additions have been installed in the guest from clean after the TTY config was set up as above and XP rebooted

When I look in Device Manager (right-click My Computer => Properties => Hardware => Device Manager), when I expand the list under "Ports (COM & LPT)", only LPT1 shows, and no COM ports.

If I do a refresh ("Scan for hardware changes"), no COM ports appear.

Showing hidden devices does not change things.

Help!

I've updated the XP guest to Service Pack 3; no difference in behaviour.

Jon

Main part of the answer is from ubuntuforums.org :
...where "cod.almighty, February 14th, 2009, 05:48 PM" says :
"...then after booting up WinXP run Start > Settings > Control Panel > Add Hardware.
the serial port didn't show up in the hardware wizard so I had to use the Advanced option (Install manually from a list.)
After doing this virtualBox recognized my serial port as COM3."

I tested it myself and it worked well, some details follows :
( WinXP guest ) >> settings >> Add Hardware >> Next (stupid win scans...) >> Yes, I ...connected... >> Next >> Add a new hardware device ( at bottom of the list ) >> Install ...that I... select... >> Show All Devices >> Next >> Standard port types (in the left list, and, in the right list select : ) Communication port >> Next

( WinXP guest ) >> settings >> system >> Hardware (tab) >> Device Manager >> Ports >> ( ...select driver ?, enable, reboot the virtual machine, whatever... )

OK, It works ! ( today ; 2010 Oct. 25 )