A dissapearing COM port

NTDEV
1

I have a customer with a device that loses its COM port after they install
my driver. This driver is installed by updating the com port in device
manager with the new driver. This works fine on thousands of Tablet PCs.
After installing on this particular unit though, and rebooting, the COM port
is not found and there is no ACPI\pnp0501 listed in the enum section in the
registry. Needless to say, this results in the driver not being loaded.
I don’t think it is caused by something my driver is doing directly but I’m
at a loss to figure out why this happens. Any explanation or suggestion
would be greatly appreciated.

-Dan

2

Is /debug on the boot.ini entry? If present on ACPI systems, there is
no com port enumerated (vs a non acpi system where the com port is !'ed
out).

D

This posting is provided “AS IS” with no warranties, and confers no
rights

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Dan Tower
Sent: Tuesday, March 09, 2004 9:15 AM
To: Windows System Software Devs Interest List
Subject: [ntdev] A dissapearing COM port

I have a customer with a device that loses its COM port after they
install
my driver. This driver is installed by updating the com port in device
manager with the new driver. This works fine on thousands of Tablet
PCs.
After installing on this particular unit though, and rebooting, the COM
port
is not found and there is no ACPI\pnp0501 listed in the enum section in
the
registry. Needless to say, this results in the driver not being loaded.
I don’t think it is caused by something my driver is doing directly but
I’m
at a loss to figure out why this happens. Any explanation or suggestion

would be greatly appreciated.

-Dan

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

3

Do you check the COM Arbiter before grabbing a port?

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com]On Behalf Of Doron Holan
Sent: 09 March 2004 17:29
To: Windows System Software Devs Interest List
Subject: RE: [ntdev] A dissapearing COM port

Is /debug on the boot.ini entry? If present on ACPI systems, there is
no com port enumerated (vs a non acpi system where the com port is !'ed
out).

D

This posting is provided “AS IS” with no warranties, and confers no
rights

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Dan Tower
Sent: Tuesday, March 09, 2004 9:15 AM
To: Windows System Software Devs Interest List
Subject: [ntdev] A dissapearing COM port

I have a customer with a device that loses its COM port after they
install
my driver. This driver is installed by updating the com port in device
manager with the new driver. This works fine on thousands of Tablet
PCs.
After installing on this particular unit though, and rebooting, the COM
port
is not found and there is no ACPI\pnp0501 listed in the enum section in
the
registry. Needless to say, this results in the driver not being loaded.
I don’t think it is caused by something my driver is doing directly but
I’m
at a loss to figure out why this happens. Any explanation or suggestion

would be greatly appreciated.

-Dan

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@des.co.uk
To unsubscribe send a blank email to xxxxx@lists.osr.com

4

If he is installing on pnp0501, the arbieter has already assigned the
port number.

D

This posting is provided “AS IS” with no warranties, and confers no
rights

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of xxxxx@des.co.uk
Sent: Tuesday, March 09, 2004 9:38 AM
To: Windows System Software Devs Interest List
Subject: RE: [ntdev] A dissapearing COM port

Do you check the COM Arbiter before grabbing a port?

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com]On Behalf Of Doron Holan
Sent: 09 March 2004 17:29
To: Windows System Software Devs Interest List
Subject: RE: [ntdev] A dissapearing COM port

Is /debug on the boot.ini entry? If present on ACPI systems, there is
no com port enumerated (vs a non acpi system where the com port is !'ed
out).

D

This posting is provided “AS IS” with no warranties, and confers no
rights

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Dan Tower
Sent: Tuesday, March 09, 2004 9:15 AM
To: Windows System Software Devs Interest List
Subject: [ntdev] A dissapearing COM port

I have a customer with a device that loses its COM port after they
install
my driver. This driver is installed by updating the com port in device
manager with the new driver. This works fine on thousands of Tablet
PCs.
After installing on this particular unit though, and rebooting, the COM
port
is not found and there is no ACPI\pnp0501 listed in the enum section in
the
registry. Needless to say, this results in the driver not being loaded.
I don’t think it is caused by something my driver is doing directly but
I’m
at a loss to figure out why this happens. Any explanation or suggestion

would be greatly appreciated.

-Dan

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@des.co.uk
To unsubscribe send a blank email to xxxxx@lists.osr.com

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@windows.microsoft.com
To unsubscribe send a blank email to xxxxx@lists.osr.com

5

Thank you for the response.
I don’t have the unit in hand so I have not been able to check the boot.ini
yet but wouldn’t this cause the port to not be enumerated all the time? As
it stands this only happens when they install my driver and reboot.

Thanks again,
-Dan

“Doron Holan” wrote in message
news:xxxxx@ntdev…
If he is installing on pnp0501, the arbieter has already assigned the
port number.

D

This posting is provided “AS IS” with no warranties, and confers no
rights

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of xxxxx@des.co.uk
Sent: Tuesday, March 09, 2004 9:38 AM
To: Windows System Software Devs Interest List
Subject: RE: [ntdev] A dissapearing COM port

Do you check the COM Arbiter before grabbing a port?

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com]On Behalf Of Doron Holan
Sent: 09 March 2004 17:29
To: Windows System Software Devs Interest List
Subject: RE: [ntdev] A dissapearing COM port

Is /debug on the boot.ini entry? If present on ACPI systems, there is
no com port enumerated (vs a non acpi system where the com port is !'ed
out).

D

This posting is provided “AS IS” with no warranties, and confers no
rights

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Dan Tower
Sent: Tuesday, March 09, 2004 9:15 AM
To: Windows System Software Devs Interest List
Subject: [ntdev] A dissapearing COM port

I have a customer with a device that loses its COM port after they
install
my driver. This driver is installed by updating the com port in device
manager with the new driver. This works fine on thousands of Tablet
PCs.
After installing on this particular unit though, and rebooting, the COM
port
is not found and there is no ACPI\pnp0501 listed in the enum section in
the
registry. Needless to say, this results in the driver not being loaded.
I don’t think it is caused by something my driver is doing directly but
I’m
at a loss to figure out why this happens. Any explanation or suggestion

would be greatly appreciated.

-Dan

—
Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

—
Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@des.co.uk
To unsubscribe send a blank email to xxxxx@lists.osr.com

—
Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@windows.microsoft.com
To unsubscribe send a blank email to xxxxx@lists.osr.com