On Tue, May 26, 2015 at 09:15:53PM +0000, Cooper Jr., Franklin wrote:
> Michael,
> 
> Can you send me the output of ts_test_raw after you done a 5 or so touch down 
> and touch up events? In the output let me know at which point in the log that 
> the issue you observed has occurred. Please try to avoid moving your finger 
> since I want to see the full output of that program but I'm not interested 
> any unnecessary pen down events.
>

Oddly the repeated pen up and down events do not occur when running 
ts_print_raw:
root@som3517-som200:~# ts_print_raw 
1418169393.147827:   1648   2075    206
1418169393.229976:   1725   1983    240
1418169393.312154:   1731   1980    240
1418169393.394333:   1706   2043    239
1418169393.476523:   1703   2028    241
1418169393.558708:   1714   2041    240
1418169393.640888:   1704   2041    240
1418169393.721556:      0      0      0
1418169395.283096:   2889   2512    192
1418169395.365236:   2947   2486    210
1418169395.447413:   2949   2470    211
1418169395.529606:   2943   2497    211
1418169395.611759:   2922   2506    211
1418169395.693935:   2866   2474    213
1418169395.776135:   2858   2481    214
1418169395.858305:   2861   2451    213
1418169395.938972:      0      0      0
1418169397.482867:   1083   1981    236
1418169397.565026:   1157   1832    254
1418169397.647217:   1161   1856    256
1418169397.729412:   1158   1883    255
1418169397.811583:   1159   1841    255
1418169397.893760:   1159   1864    256
1418169397.975947:   1158   1893    256
1418169398.056605:      0      0      0
1418169399.690290:   2299   2372    178
1418169399.772432:   2388   2160    221
1418169399.854611:   2391   2190    223
1418169399.936802:   2379   2207    223
1418169400.018966:   2389   2184    223
1418169400.101146:   2383   2208    224
1418169400.183338:   2381   2203    223
1418169400.264012:      0      0      0
1418169402.073266:   1230   2381    212
1418169402.155413:   1301   2097    247
1418169402.237590:   1313   2077    248
1418169402.319772:   1307   2126    248
1418169402.401948:   1304   2096    248
1418169402.484127:   4078   2155     58
1418169402.564801:      0      0      0

Here is what the output of ts_test looks like without even touching the screen:
root@som3517-som200:~# ts_test               
1418169549.722957:    816     17     58
1418169549.803604:    816     17      0
1418169549.817757:    816     25     58
1418169549.898411:    816     25      0
1418169549.912828:    816     41     59
1418169549.993463:    816     41      0
1418169550.007771:    816     28     58
1418169550.088404:    816     28      0
1418169550.102828:    816     33     58
1418169550.183486:    816     33      0
1418169550.197767:    816     42     59
1418169550.278401:    816     42      0
1418169550.292970:    816     23     58
1418169550.373604:    816     23      0
1418169550.387773:    816     28     58
1418169550.468404:    816     28      0
1418169550.482955:    816     32     59
1418169550.563600:    816     32      0
1418169550.577773:    816     25     58
1418169550.658406:    816     25      0
1418169550.672827:    816     35     59
1418169550.753464:    816     35      0
1418169550.767761:    816     42     59
1418169550.848407:    816     42      0
1418169550.862826:    816     41     59
1418169550.943462:    816     41      0
1418169550.958013:    816     37     59
1418169551.038655:    816     37      0
1418169551.052824:    816     41     59
1418169551.133475:    816     41      0
1418169551.147774:    816     28     58
1418169551.228406:    816     28      0
.
.

> I recently encountered several touchscreen problems that I am working on 
> submitting to mainline. Below are the variety of issues I discovered and 
> fixed but its currently based on 3.14 kernel.
> 
> 1. The x and y location right before a penup event is usually incorrect. 
> Visibly the causes the cursor to jump right before a touchup. So I 
> implemented a way to ignore that incorrect event.
> 2. I discovered that for some reason a series of touch up events are sent 
> back to back. So I added something to ignore consecutive pen up events.
> 3. Sometimes a pen down event is reported with a pressure of 0. I noticed 
> applications like ts_lib looked at the pressure and thought a pressure of 0 
> means a finger was lifted. So I added a patch that ignored 0 pressure pen 
> down events. This prevented premature touchups.
> 4. I added debouncing. Essentially the driver didn't report any touch events 
> for a user specified number of ms after a pen up occured. It was noticed 
> especially during touchscreen calibration that after a person lifted their 
> finger after touching the screen a combination of pen up and pen down events 
> were incorrectly detected.
> 
> Most likely a combination of 2-4 is your problem. I think the udelay acted 
> like an unintentional debounce which is probably why it wasn't discovered 
> sooner.
> > >
> > > --
> > > balbi
> > 
> 
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