OpenBSD does not support extended PS/2 mouse protocols ("xxxPS/2").
The PS/2 mouse device driver /dev/pms emulates the bus mouse.
Specify the "BusMouse" protocol for
any PS/2 mouse regardless of the brand of the mouse when using this device.
The raw PS/2 mouse device driver /dev/psm uses the standard PS/2
mouse protocol.
Therefore, you should specify the "PS/2" protocol for
any PS/2 mouse regardless of the brand of the mouse when using this device.