Gentoo kernel 3.6.11 webcams, V4L, UVC, video: kernel config

For those of us adventurous enough to upgrade to the Gentoo kernel 3.6.11 using their own custom kernel config… Beware that the config spec for the video modules and webcam modules including all of the USB UVC/video have been moved in the config hierarchy and may well need reenabling:

Lost your /dev/video0 and you have a custom config for your kernel? Check that you still have enabled the appropriate kernel modules for:

CONFIG_MEDIA_CAMERA_SUPPORT:

Enable support for webcams and video grabbers.

Say Y when you have a webcam or a video capture grabber board.

Symbol: MEDIA_CAMERA_SUPPORT [=y]
Type  : boolean
Prompt: Cameras/video grabbers support
  Defined at drivers/media/Kconfig:21
  Depends on: MEDIA_SUPPORT [=m]
  Location:
    -> Device Drivers
      -> Multimedia support (MEDIA_SUPPORT [=m])

And then followed by:

CONFIG_USB_VIDEO_CLASS:

Support for the USB Video Class (UVC).  Currently only video input devices, such as webcams, are supported.

For more information see: 

Symbol: USB_VIDEO_CLASS [=m]
Type  : tristate
Prompt: USB Video Class (UVC)
  Defined at drivers/media/video/uvc/Kconfig:1
  Depends on: MEDIA_SUPPORT [=m] && VIDEO_CAPTURE_DRIVERS [=y] && VIDEO_V4L2 [=m] && V4L_USB_DRIVERS [=y] && MEDIA_CAMERA_SUPPORT [=y]
  Location:
    -> Device Drivers
      -> Multimedia support (MEDIA_SUPPORT [=m])
        -> Video capture adapters (VIDEO_CAPTURE_DRIVERS [=y])
          -> V4L USB devices (V4L_USB_DRIVERS [=y])
  Selects: VIDEOBUF2_VMALLOC [=n]

That is, in the kernel config, enable:

Device Drivers -> Multimedia support
Device Drivers -> Multimedia support -> Video capture adapters -> V4L USB devices

… And compile, install and reboot.