I'm having this same problem in my Vaio, but manually unloading/reloading the uvcvideo does not fix the problem.
The webcam was working in Karmic, not with the stock uvcvideo modules, but with a self-compiled drivers for uvcvideo donwloaded from upstream svn.
Unfortunately, selfcompiling the last svn modules does not fix this issue in Lucid.
I'm having this same problem in my Vaio, but manually unloading/reloading the uvcvideo does not fix the problem.
The webcam was working in Karmic, not with the stock uvcvideo modules, but with a self-compiled drivers for uvcvideo donwloaded from upstream svn.
Unfortunately, selfcompiling the last svn modules does not fix this issue in Lucid.