Module windows-serialmouse

Microsoft Windows sometimes it detects other serial devices as a serial mouse. If the device is connected to a real TIA-232 port or a Universal Serial Bus (USB) to TIA-232 adapter. Some USB connected devices, e.g. GPS receivers, have USB to TIA-232 convertors built right into the device. This Viam module disables the serial mouse if Windows has re-enabled it.

https://paulhutch.blog/2019/06/24/disable-serial-mouse-detection/

Models

This module provides the following model:

• Model viam-soleng:windows-serialmouse:disable

windows-serialmouse

Call the DoCommand of this model to apply two registry changes that stop Windows from treating the serial line as a serial mouse:

1. Disable the sermouse service. The module queries the registry and, if Start is 3, changes it to 4.

   Location: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\sermouse
   Key: Start
   Value: 3 -> 4
   

2. Skip serial port enumeration. For every built-in serial port instance under PNP0501, the module writes a SkipEnumerations DWORD of 0xffffffff so Windows stops polling those COM ports for a mouse. The Device Parameters subkey and value are created if they do not already exist.

   Location: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Enum\ACPI\PNP0501\<instance>\Device Parameters
   Key: SkipEnumerations (DWORD)
   Value: 0xffffffff
   

   PNP0501 is the ACPI ID for the built-in 16550 serial port. A device on a USB-to-serial adapter or a different ACPI ID will not be covered by this step.

Configuration

There are no configuration attributes required for this module.

Attributes

There are no configuration attributes required for this module.

Example Configuration

{
}

DoCommand

This module implements the DoCommand. Periodically send it an empty {} via the Viam Job Scheduler.

Example DoCommand

{
}

Response

{
  "start": 4,
  "changed": true,
  "message": "Start value changed from 3 to 4",
  "enumeration_disabled_ports": [
    "System\\CurrentControlSet\\Enum\\ACPI\\PNP0501\\1\\Device Parameters"
  ]
}

• changed — whether the sermouse Start value was updated this call (false if it was already 4).
• enumeration_disabled_ports — the ports where we disabled serial-mouse enumeration; that is, the Device Parameters paths where SkipEnumerations was written. Empty if no PNP0501 serial port instances were found.