使用虚拟桌面时串行鼠标设备崩溃

Question

I have some old serial based USB touchscreen systems that would be expensive to replace with new hardware.

They are connected in the following manner:

Serial Mouse -> Serial to USB adapter -> Thin Client -> Virtual Machine

Everything works great with one issue. I'm experiencing a driver crash everything user either logs off, shutdown, or reboots. The current workaround has been to disable the serial mouse device before logging off which is a real pain. As long as the device is disabled, everything works great.

I did a lot of research on this issue by taking memory dumps of the crash virtual machines.

It seems like when the user logs off, the USB device is abruptly disconnected and then Windows tries to disable the device gracefully and waits until it is confirmed, thus hanging forever. In assembly it appears to call a .sys file that never returns back.

Is there anything that can be done with an issue like that? Can you change the device shutdown order? Or perhaps tell Windows to not ensure the plug and play device is shutdown? I doubt the vendor would be willing to change their driver.

Answer 1

I wrote a custom solution to this problem.

The application uses the ShutdownBlockReasonCreate API call to block Windows from shutting down. It then listens for reboots or logoffs using the WM_QUERYENDSESSION API call. When it gets this, it disabled the devices and then destroys the shutdown block created.

A real pain but it works