If I correctly understand how serial ports work under XP, they have two
symbolic links,
A PnP link with the name ??\ACPI#PNP0501#0#{GUID} and
A link with the name ??\Serial0
Additionally a mapping exists in the hardware serialcomm registry that
links “COM1:” to ??\Serial 0
I am using an rs232 port from an ndis driver and receive notification of
PnP0501 device arrivals to locate serial ports.
How can I resolve the xxxxx@X device name to a comx: name or a
??\serialx name?
Larry Harmon
(1) Get Winobj.exe and look at the symbolic links in ?? to see how Device
Names like Com get resolved to the driver.
(2) Also let me mention Com Name Arbiter in the register is a bitmask of Com
ports in use.
Sincerely;
William Michael Jones
“Larry Harmon Sr.” wrote in message news:xxxxx@ntdev…
> If I correctly understand how serial ports work under XP, they have two
> symbolic links,
> A PnP link with the name ??\ACPI#PNP0501#0#{GUID} and
> A link with the name ??\Serial0
>
> Additionally a mapping exists in the hardware serialcomm registry that
> links “COM1:” to ??\Serial 0
>
> I am using an rs232 port from an ndis driver and receive notification of
> PnP0501 device arrivals to locate serial ports.
>
> How can I resolve the xxxxx@X device name to a comx: name or a
> ??\serialx name?
>
> Larry Harmon
>
>
>
>
You should not touch the bitmask directly that the com name arbiter
uses. Use the user mode APIs exported out of msports.dll to do that.
The only time you should be claiming / releasing a name is at device
install time where the user mode class installer can do all of this for
you. If you install under the “Ports” class, you don’t have any work to
do.
This bitmask does not map from the device interface string (??\ACPI…)
to the legacy DOS name (ie com1:) nor the device name (\Device\SerialX).
It just a list of port names that have been claimed by devices on the
machine.
d
-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Michael Jones
Sent: Friday, January 14, 2005 1:42 PM
To: Windows System Software Devs Interest List
Subject: Re:[ntdev] serial port symbolic link names
(1) Get Winobj.exe and look at the symbolic links in ?? to see how
Device
Names like Com get resolved to the driver.
(2) Also let me mention Com Name Arbiter in the register is a bitmask of
Com
ports in use.
Sincerely;
William Michael Jones
“Larry Harmon Sr.” wrote in message
news:xxxxx@ntdev…
> If I correctly understand how serial ports work under XP, they have
two
> symbolic links,
> A PnP link with the name ??\ACPI#PNP0501#0#{GUID} and
> A link with the name ??\Serial0
>
> Additionally a mapping exists in the hardware serialcomm registry that
> links “COM1:” to ??\Serial 0
>
> I am using an rs232 port from an ndis driver and receive notification
of
> PnP0501 device arrivals to locate serial ports.
>
> How can I resolve the xxxxx@X device name to a comx: name or a
> ??\serialx name?
>
> Larry Harmon
>
>
>
>
—
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