I have been playing with touchscreens for the last couple weeks. I noticed 
the following:

For both 4.3" and 7" resistive touchscreens I have, the jitter is 
significantly better in the default Angstrom versus Debian. Angstrom 
jitters with around 5pixels of the touched point, Debian is >20pixels

Looking at Debian, it seems to have a much newer version of the touchscreen 
driver than Angstrom does. I believe this is the revision angstrom uses:

Last time steps_to_configure was available:
https://github.com/torvalds/linux/commit/af9c2fe3740fe8dac05eede8805d9aaa45972cb6

Change from steps_to_configure to coordinate_readouts:
https://github.com/torvalds/linux/commit/0396310b0eba71595c1151ce7c8fde7a9f33f719


Angstrom's DTC files for touchscreen refer to 'steps-to-configure' where 
Debian's has the newer 'coordinate-readouts'.

I would be happy if the quality of touch input that I get from Angstrom 
existed in Debian, so I'll try to compile the old driver, then recompile my 
DTC files and use steps_to_configure and report back.


On Friday, 14 March 2014 15:19:28 UTC-7, Piotr Murawski wrote:
>
> There is a part in the driver (ti_am335x_tsc.c):
>
>     config = STEPCONFIG_MODE_HWSYNC |
>             STEPCONFIG_AVG_16 | ts_dev->bit_yp |
>             ts_dev->bit_xn | STEPCONFIG_INM_ADCREFM |
>             STEPCONFIG_INP(ts_dev->inp_xp);
>     titsc_writel(ts_dev, REG_STEPCONFIG(end_step), config);
>     titsc_writel(ts_dev, REG_STEPDELAY(end_step),
>             STEPCONFIG_OPENDLY);
>
>     end_step++;
> *&*
> ...

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