Guest XP doesn't start with serial interface enabled.

[P-Ingo]

Hardware: ThinkPad X61 + UltraBay (COM Port)
Software: VBox: 6.0.8 / Host: Xubuntu 19.04 64Bit - Guest: Windows XP SP2

Preliminary remarks
I need to run XP as a VBox guest with serial interface. The Ultrabay dock of my ThinkPad X61 still got such a COM Port.
On my ThinkPad there is an other bootable partition with Windows XP and the PLC software installed.
I tested the serial interface and everything runs fine. -> No hardware issues.

Linux Configuration
- I am member of the dialout group.
- Serial port is present ttyS0 - Terminal: $ ls -l /dev/ttyS0 -> Output: crw-rw---- 1 root dialout 4, 64 Jun 3 14:39 /dev/ttyS0
- Serial port is present ttyS0 - Terminal: ~$ dmesg | grep ttyS0 -> Output: ttyS0 at I/O 0x3f8 (irq = 4, base_baud = 115200) is a 16550A

VBox Configuration
serial port: enable
port number: COM1
IRQ and port: 4 and 0x3F8
Port Mode: Host Device
Port Path: /dev/ttyS0

Failure description:
When serial port is enabled, the virtual machine starts, XP bootlogo shown.
-> Windows gets frozen after 3 - 4 seconds.
When serial port disabled, the virtual machine starts and XP guest runs.

Please help ! I spent already hours on the VBox forum and with google. Couldn't find a solution.

[andyp73]

Can you try VirtualBox 5.2.30 available from the old builds pages? There were significant changes to the serial port code in VirtualBox 6.0.x and it would be good to get a baseline of what works and doesn't for your system. It would also be good to know if any of the previous 6.0.x versions worked too.

If there is a VBox.log file from a session where it froze with the serial port enabled then zip that and post it to the thread as well.

-Andy.

[P-Ingo]

Hi andyp73 !

Thanks for your ideas. I will check one of my other X61 ThinkPads if there is still a VBox V5.2.x is installed.
On this X61 I would like to avoid to go back to V5.2.x because there are a lot of VM updated and running with VBox 6.x
Don't think a parallel installation of V5 and V6 could be possible.

I extracted some messages from VBox.log

00:00:01.592419   Serial0IoPortBase   <integer> = 0x00000000000003f8 (1 016)
00:00:01.592423   Serial0Irq          <integer> = 0x0000000000000004 (4)

00:00:01.754285 Serial#0: emulating 16550A (IOBase: 03f8 IRQ: 4)
00:00:01.754998 Serial#0: Failed to change parameters to 9600,NONE,5,1 -> VERR_DEV_IO_ERROR
00:00:01.755026 Serial#0: Failed to query status line status with VERR_DEV_IO_ERROR during reset

00:00:02.755736 HostSerial#0: Status line monitoring failed at a lower level and is disabled

00:00:15.752794 Serial#0: Failed to change parameters to 9600,EVEN,7,1 -> VERR_DEV_IO_ERROR
00:00:15.753002 Serial#0: Failed to change parameters to 1200,EVEN,7,1 -> VERR_DEV_IO_ERROR

[mpack]

It might also be worth checking that the serial port actually works - not just is present - on the host too. I wouldn't leap to the conclusion that a lockup is a VirtualBox problem.

And make sure that the port is available for use: e.g. if it is opened by an OS task such as a printer queue then it isn't available for the VM.

Also, we really need to see the entire log, not just an excerpt: zip the log and attach it to a post.

[P-Ingo]

Hi Andy,

problem "solved". Your idea to try 5.2.30 was correct . With this version it works.

I took an other ThinkPad X61 to try. Had to de-install V6.0.8 first because it isn't possible to run two different VirtualBox versions on the same system. By the way both run with the same Xubuntu 19.04 64bit. So it isn't a problem o the OS.

Unfortunately it isn't really solved as it isn't still working on VBox 6. Who wants to downgrade now ?

Hope Oracle could work on this. I don't think they really need my log file for this.
Quite sure it will not work with every other laptop, Xubuntu 19.04 and VBox 6.x

Folks thanks for the ideas.

[andyp73]

This looks a bit like bug #18668 Problem with sharing serial port after upgrade from 5.2.28 to 6.0.X albeit that you are seeing a different error in the log file - VERR_INVALID_PARAMETER to your VERR_DEV_IO_ERROR.

-Andy.

[P-Ingo]

Yes, seems to be a very similar problem. Would be nice if Oracle could fix this for V6.xx.

Probably I will open a topic: "Who runs Windows as a guest on Linux host with VBox V6.xx with working serial interfaces" ?
In my opinion the serial interface is a quite important interface on a virtual machine to keep old soft-/hardware alive.

[socratis]

Probably I will open a topic:

No, don't bother, it is known that serial ports have issues...

I would suggest to either stick with 5.2.30, or start testing the Test 6.0.x Builds, or the Development Builds from https://www.virtualbox.org/wiki/Testbuilds

[P-Ingo]

socratis, yes currently I have no choice than to downgrade and use again 5.2.30
Luckily I can keep one of my ThinkPads for this task, as from time to time I need this serial port connection for an old PLC
software running on XP.

On my daily "job-ThinkPad" I cannot downgrade from 6.0.8, because all VMs (> 25) are already updated (Guest additions) to VBox 6.x . I cannot loose time for down- / upgrading.

Hope this 6.x bug will be fixed soon.

[socratis]

Hope this 6.x bug will be fixed soon.

Not by itself it won't.
Why don't you add your voice/logs to the ticket? The more data points, the better chances for the developers to pinpoint the issue.