RegisterDeviceNotification and device driver initialization.

[sam]

Hi ,

we are having a problem detecting our custom usb devices with RegisterDeviceNotification.

The problem seems to be that the notification WM_DEVICECHANGE reaches the application before the device driver has properly loaded. And this does not happen everytime , 70% of the times devices are successfully opened after receiving the notification. but otherwise they fail with "device not found" type messages.

So we want to know , does the WM_DEVICECHANGE message is sent after the complete and proper loading/initilization of the driver has taken place?

Thanks

[Geoff]

Windows sends more than one WM_DEVICECHANGE message to all top level
windows. The application must examine the wParam of the message and
only access the device after finding DBT_DEVICEARRIVAL.

http://msdn.microsoft.com/en-us/library/aa363215(v=vs.85).aspx

[sam]

Hi,

We are already catching DBT_DEVICEARRIVAL and only then trying to open then device, but still this issue is there.

Is there any other way we can check if the driver has completed loading/initialization and then we can try to open the device?

Thanks