Dmitry Torokhov wrote on 2010-10-22: > Hi Michael, > > On Mon, Oct 18, 2010 at 03:33:24PM +0200, michael.hennerich@xxxxxxxxxx > wrote: >> From: Michael Hennerich <michael.hennerich@xxxxxxxxxx> >> >> Considering following scenario - the touch is present on the screen at >> the beginning of the last conversion sequence, but by the time the last >> sequence is finished, the finger is lift off. The AD7879 data available >> interrupt signals (DAV) completion, however some X,Y values are not >> valid because the screen inputs were floating during the acquisition. >> >> The AD7877 acts differently here, since it only asserts DAV if the >> touch is still present when the conversion sequence finished. >> >> Based on the fact that this can only happen in the last sample of the >> repeated conversion sequence. We simply skip the last. (Short glitches >> are filtered by the AD7879 internal median and average filters) This >> doesn't cause noticeable side effects, since the minimum conversion >> interval is 9.44ms. We receive ~100 waypoint samples per second, so we >> simply delay the result by 9.44ms. >> >> Actually this patch repeats the first waypoint twice and then skips > the last. > > Input core won't actually pass the 2nd instance through. I think the > whole thing should look like the patch below. I know input core suppresses identical events. Your patch looks nicer, however it will delay the first response by one Interrupt. Considering the minimum automatic conversion interval of 9.44ms - Not sure how much this really matters. Acked-by: Michael Hennerich <michael.hennerich@xxxxxxxxxx> Greetings, Michael Analog Devices GmbH Wilhelm-Wagenfeld-Str. 6 80807 Muenchen Sitz der Gesellschaft Muenchen, Registergericht Muenchen HRB 4036 Geschaeftsfuehrer Thomas Wessel, William A. Martin, Margaret Seif -- 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
