At Wed, 13 Oct 2010 13:13:00 +1000, Peter Hutterer wrote: > > On Fri, Oct 08, 2010 at 07:22:32PM +0200, Takashi Iwai wrote: > > Limit the movement size for avoiding the unexpected pointer jumps. > > what pointer jumps? this patch really needs more explaining on how these > jumps happen, under what conditions, etc. simply limiting on a fixed set is > not enough.
This patch is basically for ST mode. I don't think this is inevitably needed for MT. > any solution like this walks the blurry line between dropping coordinates > and unexpected jumps, and neither is really acceptable (the first one > definitely isn't). going 1/5 of the touchpad in one movement isn't actually > hard, my finger is about 1/4 the width of my touchpad, so just moving the > finger a little bit easily covers more than 1/5 (and yes, that's normal > movement). > > a driver solution to this that tries to cater for touchpad movement also > completely ignores pointer acceleration. a user may have the pointer slowed > down to a point where even 1/2 the size of a touchpad is a normal movement. OK, the size is arguable. But a bigger finger size shouldn't be an issue in this case because a big finger movement is still reported continuously. The background of this patch is that the device sometimes doesn't report the finger off from the pad, instead it sends z with a high value in the last packet, then stops sending packets. Thus the driver still keeps tracking the position as a part of continuous pointer movement when you touch again at a totally different point, which results in a jump. If you have a better idea how to filter out such a case, it'd be great. thanks, Takashi _______________________________________________ [email protected]: X.Org development Archives: http://lists.x.org/archives/xorg-devel Info: http://lists.x.org/mailman/listinfo/xorg-devel
