AGX Xavier Hang Issue on sudden Power cycle

Hi Nvidia Team,

We are using Jetson AGX Xavier SOM on our custom carrier board. We are booting the SOM on AUTO_ON no MCU Mode rather than the Button Press ON mode as in DEVKIT. We have followed the Optional ACOK circuitry as mentioned in the “Jetson AGX Xavier Series OEM Product Design Guide”.
AGX SOM boots normally when powered ON, but whenever there is a sudden power cycle (which is less than 3/4th second) the SOM gets hanged. We need to power OFF the carrier board and wait for 2 seconds to power ON and the SOM to boot.
Kindly suggest us what might be the concern and how to resolve it.

The ext4 filesystem has a journal, which means it keeps track of what was actually written versus what is just cached during a disk write. Power off as a means of shutdown is not considered “normal operation”, and should not be used as a power down method since the next boot requires the journal to backtrack the cached content (to delete all content which was just cached and not yet written). This means some content is lost every time this occurs, but the ext4 remains uncorrupted (if corrupted, then every future write will possibly increase corruption and make the system unusable). Should the amount not written exceed the journal size, then the system becomes unbootable until repair is complete, and that repair might also be unbootable.

I don’t know if filesystem repair is the cause of hang, or if it is something else, but what you really need is to keep a serial console log going, and to save this whenever the power issue hits. Serial console shows logs even before the Linux kernel boots, and since it is logged to another PC, the log will survive a power surge (unless of course the PC also shuts down). It would be quite valuable to see the boot stage logs after a power event.


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