Serial Enumeration - starting over?

NTDEV
1

Hi,

I’ve been uninstalling and installing my serial driver for months now,
with and without updates to the parent driver. As a result, I now find
myself with ridiculously high COM port numbers assigned to my devices, and
it’s causing me grief trying to test them with 3rd party software.

I’ve searched all morning but cannot for the life of me find the
information on how to clear the COM port database and force winxp to start
enumerating new ports from scratch again - it’s driving me CRAZY!!!

Can anyone please enlighten me on how to achieve this?

TIA
Regards,

–
Mark McDougall, Engineer
Virtual Logic Pty Ltd, http:
21-25 King St, Rockdale, 2216
Ph: +612-9599-3255 Fax: +612-9599-3266</http:>

2

Use Ghost and restore the OS on the test system.

–
David J. Craig
Engineer, Sr. Staff Software Systems
Broadcom Corporation

“Mark McDougall” wrote in message news:xxxxx@ntdev…
> Hi,
>
> I’ve been uninstalling and installing my serial driver for months now,
> with and without updates to the parent driver. As a result, I now find
> myself with ridiculously high COM port numbers assigned to my devices, and
> it’s causing me grief trying to test them with 3rd party software.
>
> I’ve searched all morning but cannot for the life of me find the
> information on how to clear the COM port database and force winxp to start
> enumerating new ports from scratch again - it’s driving me CRAZY!!!
>
> Can anyone please enlighten me on how to achieve this?
>
> TIA
> Regards,
>
> –
> Mark McDougall, Engineer
> Virtual Logic Pty Ltd, http:
> 21-25 King St, Rockdale, 2216
> Ph: +612-9599-3255 Fax: +612-9599-3266
></http:>

3

What you’re looking for… Is the COM Arbiter registry value.

All the information is in the source for serial.sys that comes with the
DDK.

BR,

Rob Linegar
Software Engineer
Data Encryption Systems Limited
www.des.co.uk | www.deslock.com

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Mark McDougall
Sent: 31 July 2007 03:49
To: Windows System Software Devs Interest List
Subject: [ntdev] Serial Enumeration - starting over?

Hi,

I’ve been uninstalling and installing my serial driver for months now,
with and without updates to the parent driver. As a result, I now find
myself with ridiculously high COM port numbers assigned to my devices,
and
it’s causing me grief trying to test them with 3rd party software.

I’ve searched all morning but cannot for the life of me find the
information on how to clear the COM port database and force winxp to
start
enumerating new ports from scratch again - it’s driving me CRAZY!!!

Can anyone please enlighten me on how to achieve this?

TIA
Regards,

–
Mark McDougall, Engineer
Virtual Logic Pty Ltd, http:
21-25 King St, Rockdale, 2216
Ph: +612-9599-3255 Fax: +612-9599-3266

—
NTDEV is sponsored by OSR

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4

Set environment variable DEVMGR_SHOW_NONPRESENT_DEVICES=1
Open device manager, select “show hidden devices” from the view menu.
You can now see & uninstall the unused ports.

Leo Havmøller.

5

I have to ask: how did you come across this piece of information. Good work.

mm
-----Original Message-----
From: xxxxx@lists.osr.com [mailto:xxxxx@lists.osr.com] On Behalf Of xxxxx@rtx.dk
Sent: Tuesday, July 31, 2007 09:19
To: Windows System Software Devs Interest List
Subject: RE:[ntdev] Serial Enumeration - starting over?

Set environment variable DEVMGR_SHOW_NONPRESENT_DEVICES=1
Open device manager, select “show hidden devices” from the view menu.
You can now see & uninstall the unused ports.

Leo Havm?ller.

NTDEV is sponsored by OSR

For our schedule of WDF, WDM, debugging and other seminars visit:
http://www.osr.com/seminars

To unsubscribe, visit the List Server section of OSR Online at http://www.osronline.com/page.cfm?name=ListServer

6

you really should not party on the value in the registry, the side
effects of doing this are undefined. You can either view non present
devices in device manager and uninstall the old devices (as suggested by
someone else in the thread) or you can call the ComDB APIs directly and
manually reclaim the port numbers that way.

d

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Rob Linegar
Sent: Tuesday, July 31, 2007 2:35 AM
To: Windows System Software Devs Interest List
Subject: RE: [ntdev] Serial Enumeration - starting over?

What you’re looking for… Is the COM Arbiter registry value.

All the information is in the source for serial.sys that comes with the
DDK.

BR,

Rob Linegar
Software Engineer
Data Encryption Systems Limited
www.des.co.uk | www.deslock.com

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Mark McDougall
Sent: 31 July 2007 03:49
To: Windows System Software Devs Interest List
Subject: [ntdev] Serial Enumeration - starting over?

Hi,

I’ve been uninstalling and installing my serial driver for months now,
with and without updates to the parent driver. As a result, I now find
myself with ridiculously high COM port numbers assigned to my devices,
and
it’s causing me grief trying to test them with 3rd party software.

I’ve searched all morning but cannot for the life of me find the
information on how to clear the COM port database and force winxp to
start
enumerating new ports from scratch again - it’s driving me CRAZY!!!

Can anyone please enlighten me on how to achieve this?

TIA
Regards,

–
Mark McDougall, Engineer
Virtual Logic Pty Ltd, http:
21-25 King St, Rockdale, 2216
Ph: +612-9599-3255 Fax: +612-9599-3266

—
NTDEV is sponsored by OSR

For our schedule of WDF, WDM, debugging and other seminars visit:
http://www.osr.com/seminars

To unsubscribe, visit the List Server section of OSR Online at
http://www.osronline.com/page.cfm?name=ListServer

—
NTDEV is sponsored by OSR

For our schedule of WDF, WDM, debugging and other seminars visit:
http://www.osr.com/seminars

To unsubscribe, visit the List Server section of OSR Online at
http://www.osronline.com/page.cfm?name=ListServer</http:>

7

xxxxx@rtx.dk wrote:

Set environment variable DEVMGR_SHOW_NONPRESENT_DEVICES=1
Open device manager, select “show hidden devices” from the view menu.
You can now see & uninstall the unused ports.

Thanks, I’ll give it a try! In the mean-time I found a work-around to
using COM39, but I should clean this up!

Regards,

–
Mark McDougall, Engineer
Virtual Logic Pty Ltd, http:
21-25 King St, Rockdale, 2216
Ph: +612-9599-3255 Fax: +612-9599-3266</http:>

8

xxxxx@rtx.dk wrote:

Set environment variable DEVMGR_SHOW_NONPRESENT_DEVICES=1
Open device manager, select “show hidden devices” from the view menu.
You can now see & uninstall the unused ports.

That worked, but didn’t reclaim the COM ports from the COM Arbiter.

I was a little naughty and edited the registry directly. This is only a
test machine - I wouldn’t do that on a real machine.

Thanks Leo, Rob!

Regards,

–
Mark McDougall, Engineer
Virtual Logic Pty Ltd, http:
21-25 King St, Rockdale, 2216
Ph: +612-9599-3255 Fax: +612-9599-3266</http:>