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omapl138 video device

Risto Hedman
Expert 1770 points

Hi,

In my Linux app i capture video clips from a webcam from /dev/video0. App is opening the device, capturing a clip and closing device and is doin this continuously. Now and then it happens that the original video0 is changing on fly to device video1 for some reason I have not found so far. I've tried to make symlinks to /etc/udev/rules.d but have not managed so far.

Could you please assist me with right syntax of symlink or some other solution. Linux is 3.3.0. Below is output to udevadm command.

root@omapl138-lcdk:~# udevadm info --query=all --name=/dev/video1

P: /devices/platform/musb-da8xx/musb-hdrc/usb1/1-1/1-1.1/1-1.1:1.0/video4linux/video1

N: video1

S: char/81:1

S: v4l/by-id/usb-046d_HD_Pro_Webcam_C920_FE6B9C1F-video-index0

S: v4l/by-path/platform-musb-hdrc-usb-0:1.1:1.0-video-index0

E: UDEV_LOG=3

E: DEVPATH=/devices/platform/musb-da8xx/musb-hdrc/usb1/1-1/1-1.1/1-1.1:1.0/video4linux/video1

E: MAJOR=81

E: MINOR=1

E: DEVNAME=/dev/video1

E: SUBSYSTEM=video4linux

E: ID_V4L_VERSION=2

E: ID_V4L_PRODUCT=HD Pro Webcam C920

E: ID_V4L_CAPABILITIES=:capture:

E: ID_VENDOR=046d

E: ID_VENDOR_ENC=046d

E: ID_VENDOR_ID=046d

E: ID_MODEL=HD_Pro_Webcam_C920

E: ID_MODEL_ENC=HD\x20Pro\x20Webcam\x20C920

E: ID_MODEL_ID=082d

E: ID_REVISION=0011

E: ID_SERIAL=046d_HD_Pro_Webcam_C920_FE6B9C1F

E: ID_SERIAL_SHORT=FE6B9C1F

E: ID_TYPE=video

E: ID_BUS=usb

E: ID_USB_INTERFACES=:0e0100:0e0200:010100:010200:

E: ID_USB_INTERFACE_NUM=00

E: ID_USB_DRIVER=uvcvideo

E: ID_PATH=platform-musb-hdrc-usb-0:1.1:1.0

E: DEVLINKS=/dev/char/81:1 /dev/v4l/by-id/usb-046d_HD_Pro_Webcam_C920_FE6B9C1F-video-index0 /dev/v4l/by-path/platform-musb-hdrc-usb-0:1.1:1.0-video-index0

I would appreciate assistance,

 

risto

  • 0
    TI__Guru** 116100 points
    What video device you have connected to board ?
    USB webcam ?
    Have you tried to delete/rename the video0 or video1 and check whether the device file /dev/videoX created ?
  • 0 in reply to Titusrathinaraj Stalin
    Expert 1770 points
    Hi Titus,

    Yes, it is a USB webcam.

    It can be removed and renamed.

    Once deleted, will not automatically pop again - I could not find right syntax for "scan", tried a number of variations

    usb 1-1: new high-speed USB device number 2 using musb-hdrc
    usb 1-1: New USB device found, idVendor=1a40, idProduct=0101
    usb 1-1: New USB device strings: Mfr=0, Product=1, SerialNumber=0
    usb 1-1: Product: USB 2.0 Hub [MTT]
    hub 1-1:1.0: USB hub found
    hub 1-1:1.0: 4 ports detected
    usb 1-1.1: new high-speed USB device number 3 using musb-hdrc
    usb 1-1.1: New USB device found, idVendor=046d, idProduct=082d
    usb 1-1.1: New USB device strings: Mfr=0, Product=2, SerialNumber=1
    usb 1-1.1: Product: HD Pro Webcam C920
    usb 1-1.1: SerialNumber: FE6B9C1F
    uvcvideo: Found UVC 1.00 device HD Pro Webcam C920 (046d:082d)
    input: HD Pro Webcam C920 as /devices/platform/musb-da8xx/musb-hdrc/usb1/1-1/1-1.1/1-1.1:1.0/input/input0
  • 0 in reply to Risto Hedman
    Expert 1770 points
    Hi

    I found it faster to change my app to scan from /dev/video0 to /dev/video9. I only have one video device connected so the number of it is the same in this case. I'll let you know how it works in long term - funny behaviour any way??

    risto