I re-installed file system (2Gb SD card) for my Overo gumstix. After i booted from SD, I found the touch screen did not work. So, I had a look in /dev/input directory. I can only see 'mice' in this folder, no 'touchscreen0'.
Then I tried different way to solve the problem. I tried:
$ nand erase 240000 20000
When I booted gumstix, the back light of screen turned on, but nothing displays on the screen. I can see 'touchscreen0' in /dev/input. I tried '/usr/bin/ts_test'. This command can detect the position when i touched screen, but just no display.
I thought my screen was faulty.
After that, I took a look the u-boot environment:
DVI? The touch screen I am using is LCD!
Ok, changed it to:
# setenv defaultdisplay lcd43
Haha, screen is working.