eGalax touchscreen calibration

[tuongnguyen]

Dear All,

Thank you for your effort and inputs to this topic! I finally have touch works on my RPi B+...

I install Xbian, evtest and follow the guidance from Mark: http://markamc.cybaman.net/?p=50. My screen is 800x480 with eGalax touch driver. After successfully running Mark's solution, both manual and automatic script from Brantje, my screen is still in wrong calibration. Below are the steps that I have my touch works:
- First, stop uimapper and xbmc, then run evtest to monitor event2, which is currently my eGalax. Note the x and y value of my screen's 4 corners.
- Start uimapper, then again run evtest to monitor even4, which is currently uimapper. Note the x and y value of 2 corners.
- I see that the axes value from uimapper is offset around 400+ for x and 200+ for y. Look at Mark's script, these value equal to (xmres - xsres) and (ymres - ysres), so I modify touchscreen.py like below:
x = (x*xscale + xoffset)*xcalib/(scaler)# + (xmres - xsres)
y = (y*yscale + yoffset)*ycalib/(scaler)# + (ymres - ysres)
- Re-start uimapper, run evtest to monitor event4, top-left corner is (x= -10, y=29), bottom right is (x=779, y=466). They are not so accurate to 800x480. But re-start xbmc, the touch behaviour is fine!

The next problem I'm facing is the lagging when playing video or .mp3 files. When playing a .mp3 file, the music is continuously corrupted / lagged. Then I stop uimapper, the lagging seems gone, but when the screen goes dim, the music is corrupted / lagged. How can I solve this? Do I have to upgrade my RPi B+ to a RPi 2?

Thanks & best regards,
TuongNguyen