Re: [PATCH 7/7] elantech: average the two coordinates when 2 fingers

["Éric Piel" <E.A.B.Piel@tudelft.nl>]

Op 02-08-10 14:29, Henrik Rydberg schreef:
> On 08/02/2010 02:13 PM, Éric Piel wrote:
:
>>> The above tells me that the MT situation did not improve much, and that the
>>> major improvement is to paper over the synaptics problem.
>> For me it has changed because my argument was "with two finger we report
>> crap anyway, so let's report the average". With the tracking, we
>> actually (often) report the real position of the fingers, so this
>> argument is not valid anymore. Now we can happily say we conform to the
>> official protocols: ST (which apparently requires to always reports an
>> actual position), and MT-A.
> 
> 
> It does not comply with MT-A as long as two semi-random corners of a rectangle
> are reported.
Fair enough. Without the tracking patch it complied with MT-A 50% of the
time, with it it's 75% of the time... I guess it's still not called
"complying" ;-)


>>> The argument to go forward implementing protocol B is that the current patch
>>> actually does proper two-finger tracking to the extent that it is possible.
>>> Since mtdev cannot improve the fact that this device does not following fingers
>>> but corners, it makes sense to treat this device specially, and implement the
>>> extra lines in the kernel to make it as good as it can be. Alternatively, one
>>> can give up the idea of using MT in this driver altogether, and just implement
>>> the mean position ABS_X/Y, old-style.
>> Do you think that if we implement full tracking in kernel, we can do
>> _better_ than the small tracking + mtdev? I don't think so (but, hey,
>> I've been tinkering with multitouch for something like 20h in my life,
>> so I might have missed something ;-) ). If you have in mind a better
>> performing algorithm, then let me know, and I'll happily implement it in
>> kernel :-)
> 
> 
> We can do better in the sense that since the device cannot comply with MT-A, we
> can do as close as possible to MT-B with less cpu usage. But frankly, the best
> solution at this stage seems to be to drop MT handling altogether, since there
> does not seem to be any plan to use it.
Ah, this alternative solution is a bit boring ;-) In addition it's not
compatible with my own master plan to eventually have the "pinch to
zoom" and "rotate to rotate" gestures work on my laptop, like in Windows ;-)

So, let's agree on just the two patches I'm going to send to support
"better than nothing" MT-protocol for now. When, later, someone has
better ideas, he can send patches to improve MT-protocol
support/compliance. Fine?

Eric
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