Hutterer: Synaptics pointer acceleration

For this week's development horror story, it would be hard to do betterthan PeterHutterer's quest to figure out how pointer acceleration works in theSynaptics driver. "Also a disclaimer: the last time some seriouswork was done on acceleration was in 2008/2009. A lot of things havechanged since and since the server is effectively un-testable, we ended upwith the mess below that seems to make little sense. It probably made sense8 years ago and given that most or all of the patches have my signed-off-byit must've made sense to me back then. But now we live in the gloriousfuture and holy cow it's awful and confusing."