UNSOLVED reComputer J202 Nano and 327S I2C bus issue

newleaf

I have successfully built and flashed a custom kernel image for the Nano to use the 327S.

I used the instructions at https://wiki.veye.cc/index.php/VEYE_CS_Camera_source_for_Jetson and the VEYE-MIPI-CAM2M source.

Everything works. I can stream video, capture images (event from Go code), and control the cut filter using Go's periph library.

Observation and question:

With the Nano, I am experiencing an odd behavior where the video0 device is not available after a cold boot (where the device is off for some period of time and powered up). From dmesg, I see

[    3.469294] veyecam 7-003b: probing v4l2 sensor
[    3.469545] veyecam 7-003b: tegracam sensor driver:veyecam_v2.0.6
[    3.480088] tegra-vii2c 546c0000.i2c: no acknowledge from address 0x3b
[    3.488825] veyecam 7-003b: probe failed
[    3.494165] veyecam 7-003b: board setup failed
[    3.502582] veyecam 8-003b: probing v4l2 sensor
[    3.502824] veyecam 8-003b: tegracam sensor driver:veyecam_v2.0.6
[    3.513797] Mass Storage Function, version: 2009/09/11
[    3.513803] LUN: removable file: (no medium)
[    3.528349] using random self ethernet address
[    3.535722] tegra-vii2c 546c0000.i2c: no acknowledge from address 0x3b
[    3.536048] veyecam 8-003b: probe failed
[    3.536051] veyecam 8-003b: board setup failed

If I reboot the device, then everything works. This is consistent. I must do a reboot after a cold boot in order for the camera to be seen.

Also, I am unable to access an I2C device that is plugged into the board. The I2C cut works fine with bus 8. But trying a device on another bus fails. I did successfully apply the USB bus firmware patch from Seeed if that has any impact.

i2cdetect -l
i2c-3	i2c       	7000c700.i2c                    	I2C adapter
i2c-1	i2c       	7000c400.i2c                    	I2C adapter
i2c-101	i2c       	tegradc.1                       	I2C adapter
i2c-8	i2c       	i2c-6-mux (chan_id 1)           	I2C adapter
i2c-6	i2c       	Tegra I2C adapter               	I2C adapter
i2c-4	i2c       	7000d000.i2c                    	I2C adapter
i2c-2	i2c       	7000c500.i2c                    	I2C adapter
i2c-0	i2c       	7000c000.i2c                    	I2C adapter
i2c-7	i2c       	i2c-6-mux (chan_id 0)           	I2C adapter
i2c-5	i2c       	7000d100.i2c                    	I2C adapter

Any thoughts on why a reboot is needed? As far as the not seeing other bus devices, it may be unrelated.

Thx!

veye_xumm

@newleaf said in reComputer J202 Nano and 327S I2C bus issue:

Any thoughts on why a reboot is needed?
Also, I am unable to access an I2C device that is plugged into the board. The I2C cut works fine with bus 8. But trying a device on another bus fails. I did successfully apply the USB bus firmware patch from Seeed if that has any impact.

Based on the symptoms you described, I think the issue lies in the matching of the i2c mux and the dtb. You may not be able to directly use our dts fragment, but instead, you need to adapt the appropriate dts fragment according to the i2c mux design of the J202 baseboard. I suggest seeking help from Seeed for this.

newleaf

Just wanted to provide a followup on this. Reached out to Seeed and they said they would order a camera and investigate further.

I also had some success on the Nano by reducing the cable length between the Nano and the camera (using a CSI-HDMI adapter from Arducam). Worked sometimes on first boot. Then stopped.

Regardless, we are nearing a deadline and decided to switch to the Xavier for a prototype. The Nano has been challenging due to reduced support from NVIDIA.

I believe you are right about device tree. Something different from first boot compared to reboot. Even with the longer cable, it was 100% consistent with this strange behavior.