Problem on wdfserial.sys driver running on Windows 7

NTDEV
1

Hi,

I am having problem with running my WDF serial driver on Windows 7.

Summary of my steps:

  1. Obtain the PCI_DEVICE_ID for the UART 16550 PCI card
  2. Add PCI_DEVICE_ID into C:\WinDDK\7600.16385.1\src\serial\serial\serial.inx file
  3. Build the serial.sys in WDK on checked build Windows 7 environment and checked build Windows XP environment
  4. Install UART 16550 PCI card into desktop, and install the serial.inf driver built from step #3
  5. Launch Hyper-Terminal for basic serial com. port testing on Windows XP and Windows 7

Problem I encounter is unable to open COM Port 3 when launching Hyper-Terminal under Win7.

By using the same source code, and rebuild on the same WDK under Checked Build XP environment, and testing on Windows XP, i do not encounter this problem.

1 interesting workaround identified to make Windows 7 COM Port 3 works are :
a) Remove the existing driver of COM1 (Device Manager -> Uninstall COM1 driver)
b) Reinstall COM1 driver
c) Reboot Windows
After reboot, the COM Port 3 that installed with the wdfserial.sys can now functioning.

Why windows XP do not require this special workaround ?

Thanks for the help.
2893

2

Any advices ?
Been working on the issue for weeks, and looking around for help.

Thanks in advance for help.

3

Just something to check:
(a) are you using the same computer h/w for both xp and win7?
(b) do they have the same # of serial ports? (go in device manager and check ‘ports’). is it possible that the win7 machine has already a com3?
(c) both machines have the same config for kernel debugger.
(d) did you try installing/using the xp driver in win7 (I assume they are 32 bit)? (just for the fun to see what happens).

Egi.

4

Hi Egi,

Thanks for comments.
Here are my answer to your question,
(a) are you using the same computer h/w for both xp and win7?
–> Yes

(b) do they have the same # of serial ports? (go in device manager and check
‘ports’). is it possible that the win7 machine has already a com3?
–>Checked, the win7 do not have com3, except the newly installed card driver is assigned to com3

(c) both machines have the same config for kernel debugger.
–>Sorry, can you educate me how to verify this ?

(d) did you try installing/using the xp driver in win7 (I assume they are 32
bit)? (just for the fun to see what happens).
–>Yes, just did it, same steps will be required to enable the driver (i.e need to uninstall the com1 driver, and reinstall again the com1 driver, and restart). Where these steps are not require for win xp

Thanks.