Please provide from terminal:
v4l2-ctl --list-devices
Depending if you get
/dev/video1
or
/dev/video0
try to see if the webcam works in vlc for example with this command from terminal:
vlc v4l2:// :input-slave=alsa:// :v4l-vdev="/dev/video1"
Also if you want to test some controls, you run:
v4l2-ctl -d /dev/video1 --list-ctrls
More about you can find here:
https://wiki.archlinux.org/index.php/Webcam_setup