Overlay applied during

Autonomous Machines Jetson & Embedded Systems Jetson Xavier NX
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1

HI,

We are using a custom board with an NX module with JetPack 5.1.2.

I am attempting to apply an overlay during uefi boot. I have included the device tree overlay in p3668.conf.common under the label OVERLAY_DTB_FILE=

During uefi I see the following debug messages:
a) Processing “EV Overlay” DTB overlay
b) then Overlay skipped.

I do not see any of the overlay segments applied once the boot process has completed. I see the code calls:
ApplyTegraDeviceTreeOverlayCommon, then
ProcessOverlayDeviceTree, and then
fdt_overlay_apply

I cannot see any errors.

Are we using the correct function calls, as listed above? What else may cause this overlay to not be applied?

I was able to apply the same overlay manually, it works just fine.

Thanks for any guidance,
Malcolm

3

Hi,

What kind of overlay are you applying?

Can you please re-compile UEFI to enable debug print?
Or attach the log if you have done so.

What do you mean with manually?

4

HI,

When you say “What kind of overlay are you applying”, what do you mean?

When I say manual it is using this command:
sudo /opt/nvidia/jetson-io/config-by-hardware.py -n “My Jetson Overlay example”
and rebooting the NX.

I will get the log for you.

Malcolm

5

Oct16Uefi-22.txt (184.9 KB)

Here is a log

Malcolm

6

Hi,

I mean what kind of device does the overlay support?
Will it happen on all kinds of devices or just some specific ones?

In that way, the overlay is directly integrated into the kernel dtb, instead of dynamically loaded by UEFI during booting. So the case is that you are using exactly the same dtb overlay file in these two scenarios, and it does not work it if it’s applied by specifying it in the flashing config file, but works if applied by using Jetson-IO tool?

7

Hi DaveYYY,

The overlay is used to apply changes to an audio code and camera, based on the type of board.

For your second question. Yes. The same overlay is being applied in both cases. It doesn’t work if applied using the flashing config file and does work using Jetson-IO.

Malcolm

8

Hi,

This is the document you are referring to, right?
https://docs.nvidia.com/jetson/archives/r35.4.1/DeveloperGuide/text/HR/ConfiguringTheJetsonExpansionHeaders.html#config-by-hardware-configure-header-s-by-hardware-module
So if it’s integrated into the kernel dtb, then it’d be working?
Have you tried adding the overlay contents to some existing dtb overlay provided in the BSP, instead of creating your own one?

9

Hi,

We were successful getting it to run. We had to enhance the eeprom assignments so the Match function would work properly.

Thanks for your help.

Malcolm

11

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