On Mon, Aug 02, 2010 at 01:22:15PM +0200, Henrik Rydberg wrote: > On 08/02/2010 01:12 PM, Éric Piel wrote: > > > 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. > > > The implemented part could also be done in userspace. Going half-way just to > circumvent buggy behavior in synaptics is really not a good idea. > What synaptics you are talking about here? Userspace driver or the in-kernel synaptics support? If the latter, then the device is not truly multitouch device (latest versions of the hardware/firmware aside) as it is capable of reportiong only one set of coordinates (X/Y) in addition to number of fingers on the surface. -- Dmitry -- 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
