[PATCH xf86-input-synaptics 0/2] Motion algo reversion

Chase Douglas chase.douglas at canonical.com
Tue Feb 7 13:07:06 PST 2012


The motion algorithm that was merged is completely broken. It has never
worked since it was merged, as far as I can tell. It depends on the
motion history differences to be correct, but the differences are
unsigned. This leads to values around UINT_MAX being accumulated,
which always occurs when calculating the time average variable tm.

I have tried to add signed casting to fix things, but I still end up
with cursor warps to the edges and corners of the screen. Rather than
bash my head against an algorithm that was never tested properly, it
seems better to revert the algorithm and reintroduce it when we're sure
it is working properly.

-- Chase


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