I have a solution!
1). grab install.me from here:
https://rcn-ee.net/deb/wheezy-armhf/v3.8.13-bone21/ and run it. It'd
downgrade your kernel
2). Change your .dts files from touchscreen drives from
ti,coordinate-readouts to ti,steps-to-configure and compile
3). Enjoy really nice touchscreen operation!
How I found this out: 3 days of fiddling with this! I noticed that the
angstrom release's touchscreen works really well. I saw their .dts files
had steps-to-configure in it instead of the newer ti,coordinate-readouts. I
then read the driver changes in ti_am33x_tsc in linus' repo and traced it
back to June 2013 which was the last time that 'step-to-configure' source
was available. I don't know how to compile this file on it's own so I
grabbed a RobertCNelson kernel from around that date (linked above). Ran
install.sh, changed and recompiled my dtbo and voila!
I'll leave it to the dedicated people here to decide if they want to merge
the two drivers together into a newer driver that's also perfect response.
Btw, the driver author wrote in the source about fixing this exact jumping
problem:
/*
* Delta filter is used to remove large variations in sampled
* values from ADC. The filter tries to predict where the next
* coordinate could be. This is done by taking a previous
* coordinate and subtracting it form current one. Further the
* algorithm compares the difference with that of a present value,
* if true the value is reported to the sub system.
*/
I see that note missing in newer versions and that section gone, so this
critical piece of code was removed for some reason.
time for the champagne :)
On Thursday, 13 March 2014 11:08:23 UTC-7, Mickae1 wrote:
>
> If you have an oscilloscope I'm sure that you can see this crazy noise ...
> . During my test i could saw the noise in the driver.
>
> I also discovered that the TI driver include a filter to the jitter issue
> =>
> module dejitter delta=100
>
> I'm sure the jitter filter from TI is much better than mine .....
>
> ... maybe it will be better to use the TI driver (TSLIB) than the default
> driver ..... .
>
>
> Robert Nelson ? Any idea how to do it ? I found some tutorial, but in my
> last tried I didn't succeeded :
>
> http://boundarydevices.com/debian-in-more-depth-adding-touch-support/
>
>
> Micka,
>
>
>
> On Thu, Mar 13, 2014 at 6:27 PM, Roop Singh <ro...@krda.ca
> <javascript:>>wrote:
>
> My apologies:
>
> -rw-r--r-- 1 root root 11K Feb 15 01:10 ti_am335x_tsc.ko
>
> The jitter does not seem to be much better with this. Worse than the
> jitter is sometimes when I press and release, there is a much larger jump,
> say 50 pixels away from my finger. I see this with a 4.3" newhaven display.
> I have some 7" screens on the way, perhaps there will be a difference there?
>
> ------------------------------
> *From:* Micka [mailto:micka...@gmail.com <javascript:>]
> *To:* beagl...@googlegroups.com <javascript:>
> *Sent:* Thu, 13 Mar 2014 00:59:42 -0800
>
> *Subject:* Re: [beagleboard] Re: Touchscreen Jitter / Jumping on
> Beaglebone Black LCD Capes
>
> Are you sure ? =>
> https://github.com/RobertCNelson/linux-dev/blob/am33x-v3.8/patch.sh#L847
>
>
> On Tue, Mar 11, 2014 at 7:38 PM, <ro...@krda.ca <javascript:>> wrote:
>
> Hi Micka,
>
> Would you be able to send me the driver you compiled with these changes?
> RobertCNelson's latest builds (-40) have ti_am335x_tsc.ko from last year.
>
> I tried the steps you provided last night, I got as far as compiling the
> kernel but the driver I made had invalid ELF data so I did not try loading
> it.
>
> Alternatively, the patch you have, which version of the ti_am335x_tsc.c
> driver
> is it meant to patch? there's been a lot of activity on ti_am335x_tsc.c.
>
> --
> For more options, visit <a href="http://beagleboard.org/discuss
>
> ...
--
For more options, visit http://beagleboard.org/discuss
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