Op 02-08-10 12:02, Henrik Rydberg schreef: > On 08/02/2010 10:17 AM, Éric Piel wrote: > >> Op 01-08-10 15:57, Henrik Rydberg schreef: >>> On 08/01/2010 01:28 PM, Éric Piel wrote: >> : >>>> I still think that for the very specific use case of scrolling when >>>> pressing one finger and moving up and dow the other one, reporting the >>>> average works better than the first finger. However, I guess this can be >>>> considered just as a drawback of the ST protocol, and fixed in userspace >>>> by using the MT protocol. >>>> >>>> What do you think? Does it look fine to you? Below is the code. >>> >>> >>> I might have lost track of what problem needs to be solved. The current patch >>> seems to implement tracking, but still does not solve the individual MT finger >>> problem. And, it uses the same definition of ABS_X/Y as before. I was also under >>> the impression that synaptics needs fixing, anyways. All of this taken together >>> sadly suggests that this patch could just as well be reverted to the original >>> one. Or? Alternatively, one could switch to the type B protocol, since no >>> further tracking improvement is possible in userspace. The implementation is >>> tidy and simple enough, I think. >> Yes, you're right, the patch I've sent was still with the "average of >> the 2 fingers", but I'm now willing to drop it. With the tracking, at >> least we can keep sending info about a real finger and avoid jumps at >> the transition 1->2, so reporting the first finger might have advantages >> over reporting the average :-) The improvement for the test case can >> just go to userspace. >> >> The tracking is still not so clever, so it's definitly not adapted to a >> type B MT protocol (think transition 2->1). > > > You need to add the tracking id and a couple of lines, but i do not see why the > 2->1 transition would be treated any differently. The one-finger coordinate > would be close to either position[0] or position[1], which would determine the > tracking id to keep. Every time you add a finger you add a new tracking id. What > is your planned support for three fingers? Yes, yes, it's probably fairly easy to do some kind of tracking. But I think that as long as the hardware does not provide such a thing, it's better to do the minimum in kernel space, just enough to be meaningful, and leave the rest to userspace. Concerning 3 fingers (and more), the hardware reports only one set of coordinates, the lower ones. So in this case, tracking is definitely not possible. Eric -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
