Finally got this working again.
- The two webcams worked perfectly on my old desktop computer with Linux kernel 2.6.30 (which has gspca 2.6.0 built in). I could send commands to them via v4l2 to change exposure etc.
- Then I ported the code to a new machine running 64-bit Ubuntu 10.04, kernel 2.6.32 (comes with gspca 2.7.0). The cam still worked, but I had no access to the controls, e.g. exposure, gain and flipping. I spent two days switching back to kernel 2.6.30/31, trying different patches posted on open source forums, modifying the kernels, making an identical OS from the old machine to the new one… no luck.
- But the solution turns out to be simple: check out the latest source code (2.9.0) from www.linuxtv.org, compile it and load it into the kernel. Bang. But I still don’t know why an identical OS with identical driver wouldn’t work on the new computer.
Well, at least problem solved, time to move forward.