4 Camera laptop capture frequently fails to open 1 camera

Question

Motion appears to work very well once it connects to a camera but it seems to frequently lose a camera although not the same camera (I have several different models) connected.

First camera failing:
[4] Error starting stream VIDIOC_STREAMON: No space left on device
[4] ioctl (VIDIOCGCAP): Inappropriate ioctl for device
2] Error selecting input 0 VIDIOC_S_INPUT: Device or resource busy
[2] ioctl (VIDIOCGCAP): Inappropriate ioctl for device
[4] Retrying until successful connection with camera
[4] cap.driver: "uvcvideo"
[4] cap.card: "FULL HD 1080P Webcam"
[4] cap.bus_info: "usb-0000:00:1a.0-1.1"
[4] cap.capabilities=0x84000001


Then I reload the uvcvideo driver and restart motion (a different camera fails):

[4] Failed to open video device /dev/video3: No such file or directory
[3] Retrying until successful connection with camera
[3] cap.driver: "uvcvideo"
[3] cap.card: "HD Pro Webcam C920"
[3] cap.bus_info: "usb-0000:00:1d.0-1.2"
[3] cap.capabilities=0x84000001
[3] - VIDEO_CAPTURE
[3] - STREAMING
[3] Error selecting input 0 VIDIOC_S_INPUT: Device or resource busy
[3] ioctl (VIDIOCGCAP): Inappropriate ioctl for device
[4] Retrying until successful connection with camera
[4] Failed to open video device /dev/video3: No such file or directory
[3] Retrying until successful connection with camera
[3] cap.driver: "uvcvideo"
[3] cap.card: "HD Pro Webcam C920"
[3] cap.bus_info: "usb-0000:00:1d.0-1.2"
[3] cap.capabilities=0x84000001
[3] - VIDEO_CAPTURE
[3] - STREAMING
[3] Error selecting input 0 VIDIOC_S_INPUT: Device or resource busy
[3] ioctl (VIDIOCGCAP): Inappropriate ioctl for device

Environment

Motion version:	3.2.12
ffmpeg version:	/usr/lib/x86_64-linux-gnu/libavformat.so.54
Libraries:	ffmpeg
Server OS:	"Ubuntu 14.04.1 LTS, kernel aas@aas-ThinkPad-T420:/var/log$ cat /etc/lsb-release DISTRIB_ID=Ubuntu DISTRIB_RELEASE=14.04 DISTRIB_CODENAME=trusty DISTRIB_DESCRIPTION=

-- KennethKron - 27 Sep 2014

Answer

I'm not sure what is your issue. From the description it seems like you have some problems with usb and uvcvideo driver. Do you expect motion to handle those issues?

This error:

VIDIOC_STREAMON: No space left on device

usually means there is not enough USB bandwidth available

-- TosiaraT - 27 Sep 2014

VIDIOC_STREAMON: No space left on device