Re: Virtual COM port with UMDF
- From: Andre <Andre@xxxxxxxxxxxxxxxxxxxxxxxxx>
- Date: Tue, 7 Aug 2007 04:22:00 -0700
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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