JP5.0 DP /dev/videoX not showing up

Hi There,

I’m evaluating JP5.0 compatibility for our project. I’m using Xavier NX devkit SOM with a custom carrier board. I previously tested the same set of hardware (same camera, carrier board and SOM) with JP46 and the camera works good.

I was able to make necessary changes on the device tree and driver for JP5.0. The kernel and device tree built without any problem. I also confirmed that the correct device tree was loaded on the Xavier NX device. There were no camera related error message in dmesg (please see attachment). I was not using jetson-io, and the cameras related nodes were included in the device tree files directly (included in sources/hardware/nvidia/platform/t19x/jakku/kernel-dts/common/tegra194-p3509-0000-a00.dtsi).

However, /dev/video0 and /dev/video1 does show up. Did I miss something for JP5.0? Thanks!

dmesg_log.txt (65.8 KB)

Looks like the ov7251 and imx385 was load and probe without problem.
Suppose need to look into the tegracam_device_register() and tegracam_v4l2subdev_register() in the probe() to know the reason.

Hi Shane,

Those two calls look good to me and I have standard error handling for them in the driver. Any other possible changes between JP5 and JP4.x may lead to this issue? Thanks!

   err = tegracam_device_register(tc_dev);
   if (err) {
   	dev_err(dev, "tegra camera driver registration failed\n");
   	return err;
   err = tegracam_v4l2subdev_register(tc_dev, true);
   if (err) {
   	dev_err(dev, "tegra camera subdev registration failed\n");
   	return err;

Hi Shane,

I think I figured it out.
Maybe there are some node name changes around the vi interface in the device tree in JP5.0? I made some additional changes according to the changes in sources/hardware/nvidia/platform/t19x/jakku/kernel-dts/common/tegra194-camera-rbpcv2-imx219.dtsi.

  • Use tegra-capture-vi instead of host1x { vi@15c10000
  • Use host1x@13e00000 { nvcsi@15a00000 instead of host1x { nvcsi@15a00000

And everything works as expected after that. Thanks for helping!