Description of problem:
Most of the time, cannot take photo with cheese

Version-Release number of selected component (if applicable):
3.14.2

How reproducible:
On my Lenovo B570 with internal 720p webcam - lsusb output:

Bus 003 Device 004: ID 04f2:b2fa Chicony Electronics Co., Ltd
 
$ lsusb -t
/:  Bus 04.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/3p, 480M
    |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/8p, 480M
        |__ Port 6: Dev 4, If 0, Class=Mass Storage, Driver=usb-storage, 480M
/:  Bus 03.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/3p, 480M
    |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/6p, 480M
        |__ Port 4: Dev 3, If 0, Class=Vendor Specific Class, Driver=, 12M
        |__ Port 4: Dev 3, If 1, Class=Vendor Specific Class, Driver=, 12M
        |__ Port 4: Dev 3, If 2, Class=Vendor Specific Class, Driver=, 12M
        |__ Port 4: Dev 3, If 3, Class=Application Specific Interface, Driver=, 12M
        |__ Port 5: Dev 4, If 0, Class=Video, Driver=uvcvideo, 480M
        |__ Port 5: Dev 4, If 1, Class=Video, Driver=uvcvideo, 480M
/:  Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 5000M
/:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 480M

Port4 Dev3 I think is the broken USB bluetooth thing in the broadcom wifi card - not relevant here probably

Steps to Reproduce:
1. Start Cheese (from dash, or from terminal to see output for debugging)
2. Try to take a photo a photo

Actual results:

Most of the time trying to take a photo results in the screen flashing (due to the 'fire flash' option), and the image window (which is fine to start with, showing the webcam's output) changing to 'there was a error playing video'. Running cheese in terminal, it gives these errors when it happens

$ cheese
libv4l2: error setting pixformat: Device or resource busy

(cheese:16493): cheese-WARNING **: Device '/dev/video0' is busy: gstv4l2object.c(2838): gst_v4l2_object_set_format (): /GstCameraBin:camerabin/GstWrapperCameraBinSrc:camera_source/GstBin:bin35/GstV4l2Src:video_source:
Call to S_FMT failed for YU12 @ 1280x720: Device or resource busy

$ cheese
libv4l2: error setting pixformat: Device or resource busy

(cheese:16533): cheese-WARNING **: Device '/dev/video0' is busy: gstv4l2object.c(2838): gst_v4l2_object_set_format (): /GstCameraBin:camerabin/GstWrapperCameraBinSrc:camera_source/GstBin:bin35/GstV4l2Src:video_source:
Call to S_FMT failed for YU12 @ 1280x720: Device or resource busy

$ cheese
Gtk-Message: GtkDialog mapped without a transient parent. This is discouraged.
libv4l2: error setting pixformat: Device or resource busy

(cheese:16563): cheese-WARNING **: Device '/dev/video0' is busy: gstv4l2object.c(2838): gst_v4l2_object_set_format (): /GstCameraBin:camerabin/GstWrapperCameraBinSrc:camera_source/GstBin:bin35/GstV4l2Src:video_source:
Call to S_FMT failed for YU12 @ 640x480: Device or resource busy

$ cheese
libv4l2: error setting pixformat: Device or resource busy

(cheese:16605): cheese-WARNING **: Device '/dev/video0' is busy: gstv4l2object.c(2838): gst_v4l2_object_set_format (): /GstCameraBin:camerabin/GstWrapperCameraBinSrc:camera_source/GstBin:bin35/GstV4l2Src:video_source:
Call to S_FMT failed for YU12 @ 640x480: Device or resource busy

$ cheese
libv4l2: error setting pixformat: Device or resource busy

(cheese:16747): cheese-WARNING **: Device '/dev/video0' is busy: gstv4l2object.c(2838): gst_v4l2_object_set_format (): /GstCameraBin:camerabin/GstWrapperCameraBinSrc:camera_source/GstBin:bin35/GstV4l2Src:video_source:
Call to S_FMT failed for YU12 @ 640x480: Device or resource busy

After it happens I try restarting cheese to take photos, which means it shows output again, but stops again most of the time whilst trying to take photos.
This also happens in burst mode, but does not seem to be a issue in video mode.

Expected results:

Takes a photo and saves it.

Additional info:

I have tried different resolutions and it makes no difference, though 1280x720 fails nearly constantly whilst lower resolutions sometimes work but most of the time it results in errors.

Running guvcview as suggested here: 
https://bugzilla.redhat.com/show_bug.cgi?id=1056267

then running cheese seems to work, though this results with this in terminal:

sys:1: Warning: g_object_weak_unref: couldn't find weak ref 0x7f0901134470(0x222d750)
sys:1: Warning: gsignal.c:2579: instance '0x2554f60' has no handler with id '302'
sys:1: Warning: g_object_weak_unref: couldn't find weak ref 0x7f64b9fd5470(0x249d750)
sys:1: Warning: gsignal.c:2579: instance '0x7f64a8005420' has no handler with id '297'