"acer_wmi.blacklist=yes" prevents the acer_wmi kernel module from loading. It's function is:
# modinfo acer_wmi | grep "description:"
description: Acer Laptop WMI Extras Driver
WMI is described here
. It provides an interface between the device specific hardware and the management functions that use the hardware. The problem is that manufacturers are inconsistent in their implementation for a given brand, and so sometimes the WMI driver can cause problems.