On Fri, 26 Dec 2008 22:16:32 -0500 "Nelson Castillo" <[email protected]> babbled:
> On Fri, Dec 26, 2008 at 9:05 PM, Werner Almesberger <[email protected]> > wrote: > > Nelson Castillo wrote: > >> A feature I would say :-) This is even better than what we have in the > >> stable kernel because we discard noise. Sometimes the last few events > >> get discarded because they do not provide reliable data, for instance > >> because not much pressure is applied. > > > > Discarding bogus data is obviously a good thing. I was more curious > > about why you collect enough data to start the filter and only then > > check if you're going to throw it all away anyhow. This may not make > > much of a difference in terms of performance, but the way you > > described it, this sounded like a feature. > > :-) Actually you might get enough data to report a point that makes > sense. And often you find out that even when the hardware reports > pen down, the last few points are not reliable. > > > By the way, is tslib obliged to deliver a point for each incoming > > event ? > > It is not. For instance, I sent the skip plug-in (no longer needed by > us) earlier > this month. > > https://lists.berlios.de/pipermail/tslib-general/2008-December/000150.html > > I got no feedback BTW... > > > If not, then it could do the same kind of discarding of bad > > events, couldn't it ? > > Sort of. With our current driver (with a timer) we can deliver events > each 5 milliseconds (HZ = 200). We would have to deliver chunks of > them (let's say 8 points each 5 milliseconds...). It gets a little weir when > we delay reporting the 'up' event. I don't know if this can be done in tslib. > You have a function there that blocks waiting for input there, I don't know if > you can somehow use a timeout with it like you do with select(2). > > The implementation would not be equivalent, it would be similar. > > IMHO the only one that can be just the same in kernel and in user-space > is the linear filter because the other filters give feedback to the interrupt > function. all in all - the point here isn't to remove tslib - just turn off tslib's filtering! keep it. just disable what you don't need anymore! -- ------------- Codito, ergo sum - "I code, therefore I am" -------------- The Rasterman (Carsten Haitzler) [email protected] _______________________________________________ devel mailing list [email protected] https://lists.openmoko.org/mailman/listinfo/devel
