Re: Virtual COM port with UMDF
- From: Andre <Andre@xxxxxxxxxxxxxxxxxxxxxxxxx>
- Date: Thu, 9 Aug 2007 04:10:00 -0700
Thanks for this hint. Actually I found why SerialPort does not like my
virtual com port.
It requests the file type using GetFileType() and accepts only 0 and 2, i.e
FILE_TYPE_CHAR or FILE_TYPE_UNKNOWN.
However, if I create a file handle as follows:
HANDLE hFile = CreateFile(L"COM3", GENERIC_READ | GENERIC_WRITE, 0, NULL,
OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL );
The file type returned by GetFileType() is 1, i.e. FILE_TYPE_DISK. So how
can I configure, that my device creates files of with type FILE_TYPE_CHAR?
BTW, I already handle the OnCreateFile event but I found nothing in the
documentation about how to return a certain file type from the OnCreateFile
method.
"Doron Holan [MSFT]" wrote:
the name of the device object itself shouldn't matter. there are many.
disasm tools for the .net framework which will show you the IDL or the
source code. you can use one of these tools to see why the component is
failing.
d
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"Andre" <Andre@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:46F1E8DA-DA36-40A6-919A-FE00C13BD1E8@xxxxxxxxxxxxxxxx
What about my question? Is
"\\\\.\\UMDFCtrlDev-e4cbea35-44d3-11dc-9762-0003ffa3650f" actually the
device
name which must be used in the serialcomm registry key. In the book
"Developing Drivers with WDF" (P. Orwick, G. Smith) p. 145 it mentions
that
this is the "Name of the Down device" which cannot be used by "clients".
This
suggests to me, that there could be another name which must be used in the
registry at [HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\SERIALCOMM].
I would like to debug into the SerialPort component of .NET, but at the
point of the error the source code is not available to me. Therefore, I
have
very little chance to see why it fails.
"Doron Holan [MSFT]" wrote:
You would have to debug the application at this point.
d
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"Andre" <Andre@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:04EC096C-433D-4BFD-BE57-DB31C5AB77FD@xxxxxxxxxxxxxxxx
Hi,
now I have included the steps you recommended. I am using the PortName
assigned by the ports class installer as symbolic link, which works
fine.
To
create the device name mapping I obtain the device name with method
IWDFDevice::RetrieveDeviceName() and use the result which leads to the
following additional serial comm device name mappings in the registry
[HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\SERIALCOMM]
...
"\\\\.\\UMDFCtrlDev-e4cbea35-44d3-11dc-9762-0003ffa3650f"="COM3"
However, still the .NET application is not able to open this virtual
com
port. Again I got the error message described in the original post.
Is there anything wrong with the device name? Must I retrieve it
somewhere
else?
Regards,
Andre
"Doron Holan [MSFT]" wrote:
you need to write the port name to HKLM\HARDWARE\DEVICEMAP\SERIALCOMM.
the
KMDF or WDM serial sample shows you how to do this. unfortunately, a
UMDF
driver cannot write to this key so that it is not possible without
external
help (either you modify the ACL of the key which is bad or you have
some
other comnponent with sufficient privleges to write to the key).
furthermore, install your device under the ports class and use the
PortName
assigned to your driver instead of a hardcoded name (COM9). You will
find
the PortName in the device node under a registry value of "PortName" :
REG_SZ.
d
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"Andre" <Andre@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:3E3932F7-194A-439B-9572-D93CD4B9F75E@xxxxxxxxxxxxxxxx
Hello,
I have created a UMDF driver, which creates a virtual serial com
port
in
three steps:
m_FxDevice->CreateDeviceInterface(&GUID_DEVINTERFACE_COMPORT,NULL);
m_FxDevice->CreateSymbolicLink(L"\\DosDevices\\Global\\COM9");
m_FxDevice->AssignDeviceInterfaceState(&GUID_DEVINTERFACE_COMPORT,NULL,TRUE);
I want to test this com port with a .NET application using the
SerialPort
component to access my driver. However, the GetPortNames() method
does
not
find this serial port. Also, if I explicitly specify COM9 as port
name
then
the component fails to open the port and throws an exception,
stating
that
"the given port name does not start with COM/com or does not resolve
to
a
valid serial port. Parameter: portName"
Must the driver take any additional steps to create a complete
virtual
serial port?
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