Usb 3.0 port problem for dev/video

Autonomous Machines Jetson & Embedded Systems Jetson TX2
1

While connect zed or etc camera to TX2’s usb3.0 port
And while check with vtl2
Sometimes it shows /dev/video0 for external camera

And sometimes it shows /dev/video1 i guess this is normal

And sometimes /dev/video2

3

Hi,
If you have multiple devices connected, the order of enumerating the cameras decides the index in /dev/videoX. Looks like you have three cameras. Are the camera all USB cameras? Or there are Bayer sensors or YUV sensors?

4

There is one camera that connected to tx2 and tx2’s own camera

5

Hi,
If the USB camera is connected and the we boot the device, it is /dev/video0 and the default camera is /dev/video1. If only the default camera is connected in booting, the default camera is /dev/video0. Your observation is normal.

6

Then what should i do. How can i solve this problem.
When i run the code it doesnt work

Even it gives video2

7

Hi,
Please look at:
https://docs.huihoo.com/linux/kernel/2.6.26/videobook/re01.html

By default nr=-1 in v4l2 drivers. You can modify driver to hard code the device number.

8

how could i modify that, can you help me?
i’m beginner for linux and jetson,

i saw a python code that shows

import re
import subprocess
device_re = re.compile(b"Bus\s+(?P<bus>\d+)\s+Device\s+(?P<device>\d+).+ID\s(?P<id>\w+:\w+)\s(?P<tag>.+)$", re.I)
df = subprocess.check_output("lsusb")
devices = []
for i in df.split(b'\n'):
    if i:
        info = device_re.match(i)
        if info:
            dinfo = info.groupdict()
            dinfo['device'] = '/dev/bus/usb/%s/%s' % (dinfo.pop('bus'), dinfo.pop('device'))
            devices.append(dinfo)
            
print(devices,"\n\n")

how to check /dev/video0 or etc. and assign to
VideoCapture("/dev/video and VariableName)

9

Hi,
You need to make modification in driver, rebuild/replace kernel image. Please refer to Kernel Customization in developer guide:
https://docs.nvidia.com/jetson/l4t/index.html#page/Tegra%2520Linux%2520Driver%2520Package%2520Development%2520Guide%2Fkernel_custom.html%23

10

thank you