AGX-Xavier CAN bus not working in jetpack 4.6

I have CAN bus working fine in jetpack 4.4 but it is not working in 4.6 (latest). After some searching I suspect that is due to a clock issue.

This is the output of the sudo cat /sys/kernel/debug/bpmp/debug/clk/clk_tree

below are some comparisons before enabling pinmux, drivers, interface etc and after for both jetpack versions in question.

4.6 [Not working]

4.6 before driver enable

[4.4 Working]

To be honest after enabling there doesn’t seem to be much difference (as far as I understand unless the osc bpmp value 14 to 15 is the deal breaker). Under these circumstances do you think updating the clock source will fix my problems?


Text dumps:
Jetpack 4.6 [Not working]
46_after.txt (29.4 KB)

[4.4 Working]
after44.txt (29.4 KB)

I noticed that the problem was due to the PCAN interface on the other end of my two node CAN bus.

I Changed the clock (of the other node) to 50Mz from 8MHz and it seem to work at 250Kbps. Not really sure why does that happen on 4.6 (Jetpack) because in v4.4 8Mz clock works fine without me twiddling anything.

Hi ganindu,
Yes CAN parent clock is changed to what you are seeing. If you want to keep it back to pll_aon,
check this:

1 Like

Hi @shgarg,

Thanks for the response. Since I got it working with a workaround and you’ve given the more long term accurate answer I’ll Ink them below and mark as solved.

Answers summary


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