Comment 1 for bug 162615

I've made another test :

For the Chicony webcam :

$ lsmod | grep uvc
uvcvideo 48644 1
compat_ioctl32 2304 1 uvcvideo
videodev 29312 4 uvcvideo,gspca
v4l2_common 18432 2 uvcvideo,videodev
v4l1_compat 15364 2 uvcvideo,videodev
usbcore 138632 9 snd_usb_audio,snd_usb_lib,uvcvideo,gspca,lmpcm_usb,usbhid,ehci_hcd,uhci_hcd

For the Logitech webcam :

$ lsmod | grep spca
gspca 608336 1
videodev 29312 4 uvcvideo,gspca
usbcore 138632 9 snd_usb_audio,snd_usb_lib,uvcvideo,gspca,lmpcm_usb,usbhid,ehci_hcd,uhci_hcd

It's seems that the Chicony webcam uses the uvcvideo module while the Logitech webcam uses the GSPCA module. The common modules are videodev and usbcore. Maybe the bug is in these modules.