Hi, all. I have tons of ideas how to improve kernel more. But I am very uncertain _then_ i'll be able to spend any time on it. So, here is what i already have, my patch to fix jitter without filtering. I think as everyone gone to .34, it may be important now.
Main idea is to slow down glamo pixplock while doing adc conversions. So, it works like this: <get ts down interrupt> <wait for vsync> <slow down glamo pixclock> <start ts adc> <wait for full adc cycle> <restore glamo pixclock> it is not really simple. busy waiting for vsync if really too long (eats cpu and so), so it were changed to waiting for hsync (i can't recall details) and i didn't find way to understand if we 'close to vsync end'. doing this without any waiting will procude small but noticeable visual effects (1 white line per second). reducing averaging sample count also required because overwise glamo will be slowed down for long time, which increase probability of visible effects. Expirements show that probability of getting wrong data is 10 or 100 times lower while glamo pixclock slowed down. I wrote proof of concept patch. It works well here for few months. Result is not ideal, worse in some aspects and better in other aspects than _filtering driver_ but much better than with default .34 driver, i can say that event data is fully usable for any kind of work after this change. One who want to test it will need to manually apply patches, because i had to extract code from my custom tree. patch: http://www.bsdmn.com/openmoko/kernel/jitterlessts34.patch As you have no need to filter, it generates significantly less events and doing less conversions, which should have positive influence on both power consumption and performance. I works here for several months in my debian. Known limitations/hacks: I can't do proper locking, so it is more like working proof of concept, it just sets pixclock to predefined portrait-mode value, that's why it shows snow in landscape mode while rotated. I don't know how to do proper allocation of 'glamo' struct. Regards, Gennady
