The acceleration, expressed as a fraction, is a multiplier for movement. The frac- tion may be rounded arbitrarily by the X server. Setting a value to -1 restores the default. XChangePointerControl can generate a BadValue error. The XGetPointerControl function returns the pointer's current acceleration multiplier and acceleration threshold.
Some numeric value falls outside the range of values accepted by the request.
Unless a specific range is specified for an argument, the full range defined by the argument's type is accepted. Any argument defined as a set of alternatives can gen- erate this error.