CAN clock changes back to OSC after apt upgrade

Hello,
We’re having trouble with making the PLLAON clock persistent for CAN. We flashed the Jetpack 4.5.1 with the modified dtb files according to the documentation at How to enable PLLAON and also with a bit of help from this topic Update The device tree for can bus pllaon
Right after flashing we can enable CAN as expected and it has the right clock PLLAON at 50MHz. Then we run ‘apt update && apt upgrade’ to bring the packages up to date and after the reboot the CAN clock is set to OSC and there is no way to select it back to PLLAON.
From the current device tree it seems that pll_aon is still enabled, but there doesn’t seem to be a way to move the can under pll_aon:

osc                                                1   38400000   14    0
    can1                                           1   38400000    3    1 vdd_aon@800000
        can1_host                                  1   38400000    1    1 vdd_aon@800000
        can1_core                                  1   38400000    1    1 vdd_aon@800000
    can2                                           1   38400000    3    1 vdd_aon@800000
        can2_host                                  1   38400000    1    1 vdd_aon@800000
        can2_core                                  1   38400000    1    1 vdd_aon@800000
...
osc_div
...
    pll_aon                                        1  400000000    2    0

Also, during the ‘apt upgrade’ procedure, the nvidia-l4t-kernel nvidia-l4t-kernel-dtbs nvidia-l4t-kernel-headers packages were updated, which we suspect is the root cause of this issue.
Is there a way to make the PLLAON clock persistent after upgrading system packages?

You can just remove nvidia related source from your apt source. So that apt-get upgrade won’t install them.

Could you please confirm if the cause of this issue is indeed the upgrading of l4t-kernel packages? If so, is this the only way to make the PLLAON clock persistent by removing the nvidia related source from apt source?

  1. apt-get upgrade does not only upgrade l4t-kernel. The whole jetpack version is being upgraded/re-installed.
  2. Could you please confirm if the cause of this issue is indeed the upgrading of l4t-kernel packages?

I don’t have any board/platform to confirm this but I am confident that apt-get upgrade will erased all the change you’ve done and make the system back to original jetpack version if you don’t remove nvidia source from the source list.

This topic was automatically closed 14 days after the last reply. New replies are no longer allowed.