usb webcam (uvcvideo) shows black on first plug in

[v_andal]

Recently I started to get strange problem. My USB camera shows black window when I plug it in first time. If I unplug it and plug it in again, then it works fine. I have Logitech QuickCam E3500 both at home and in the office and until recently they worked perfectly. Unfortunately I can't say when things started to be strange since I don't reboot my office machine very often But now both at home and in the office I get the same behavior.

Kernel 3.6.11-gentoo. Driver is compiled as module. In dmesg I couldn't find anything special. Just one line

usbcore: registered new interface driver uvcvideo

This line appears after first plug in, but not after the second.

Any advice on where to search? It is really strange, because the mic built in into camera works, the green light indicating camera being active is on, but the produced image is just black square. I've even tried to load uvcvideo before plugging the camera, but it didn't help.