我安装了 Guest Additions，并使用 AppleUSBVideoSupport 文件安装了 isight-firmware-tools，但仍然无法访问 iSight 网络摄像头。
当我启动 >vlc v4l2:///dev/video0 时出现以下错误：
Blocked: call to unsetenv("DBUS_ACTIVATION_ADDRESS")
Blocked: call to unsetenv("DBUS_ACTIVATION_BUS_TYPE")
[0x92d492c] main libvlc: Running vlc with the default interface. Use 'cvlc' to use vlc without interface.
Blocked: call to setlocale(6, "")
Blocked: call to setlocale(6, "")
(process:2922): Gtk-WARNING **: Locale not supported by C library.
Using the fallback 'C' locale.
(vlc:2922): Gtk-WARNING **: Unable to locate theme engine in module_path: "pixmap",
(vlc:2922): Gtk-WARNING **: Unable to locate theme engine in module_path: "pixmap",
(vlc:2922): Gtk-WARNING **: Unable to locate theme engine in module_path: "pixmap",
(vlc:2922): Gtk-WARNING **: Unable to locate theme engine in module_path: "pixmap",
[0x963287c] v4l2 demux error: VIDIOC_STREAMON failed
[0x963287c] v4l2 demux error: cannot set input (Device or resource busy)
[0x96430a4] v4l2 access error: VIDIOC_STREAMON failed
[0x96430a4] v4l2 access error: cannot set input (Device or resource busy)
[0x9371104] main input error: open of `v4l2:///dev/video0' failed: (null)