Jetson AGX won't boot with display attached - Synchronous Exception at 0x0000000857C4F798

I have an Jetson AGX running Jetpack 5.1 on a custom board which won’t boot, when a display is attached to the display port. The boot stops at the first nvidia logo screen with “Synchronous Exception at 0x0000000857C4F798” and then restarts.
Without a screen attached, the device boots just fine.
Also, with Jetpack 5.0.2 the device boots fine with display attached.

log_dp.txt is the serial log when a display is attached. The error occurs around line 1555 and the device resets itself on 1633.
log_nodp.txt is the serial log when no display is attached.
Both logs are with UEFI in debug mode.

Thanks very much in advance for your help,

log_dp.txt (97.9 KB)
log_nodp.txt (158.0 KB)

Please test with jp5.1.1 and also check if your issue could be reproduced with NV devkit.

BTW, are you sure this log has no display connected? I still see display log coming out in kernel

log_nodp.txt is the serial log when no display is attached.

Hi Wayne
Thanks for the input.

The issue is also present with JetPack 5.1.1

I can’t really test our config on the devikit, since the devkit uses the DP2 lane and in our config we use DP0 with DP2 disabled.

Sorry for the confusion about log_nodp.txt. The display is attached around 1s after turning on the power of the device, which results in a succesful boot.


I don’t get your point that devkit uses DP2 lane.

Devkit can support DP0 for displayport too… The 2 type C port on AGX devkit are the DP port too.

Hi Wayne
My bad, I totally forgot DP over USB-C was a thing.
The device behaves the same on the devkit (won’t boot with display attached to either USB-C connector, but boots if the screen is disconnected during power-on)

Does that happen to every kind of monitor?

I tested with a Samsung S24E450 1920x1080 monitor with DP cable, an acer B233HU 2048x1152 monitor with HDMI cable and an acer B193 1280x1024 monitor with DVI cable and an HDMI-DP, a DVI-DP, a DVI-HDMI and a HDMI-USBC adaptor. The issue is the same with all monitors and adaptor combination. However, with the acer B233HU, the device won’t output anything on the screen and just keeps resetting.

Please use the serial console log to tell if they all hit the same issue.

I mean just using “display has no output” is not a precise way to check when doing debug.

Hi Wayne,

here are the console logs with the different monitors. As I had to replace my serial receiver, I also re-recorded with no monitor attached (now for the full boot time ;) ). With the new serial receiver, the Synchronous Exception is around line 2940.
Also attached, you’ll find the .conf, .cfg and .dtb files for this carrier. Of course, it’s our job to solve out config files, if there’s something wrong with them, maybe you have a good idea where to look.

log_B193.txt (138.4 KB)
log_B233HU.txt (137.8 KB)
log_no_monitor.txt (142.0 KB)
log_s24e450.txt (134.2 KB)

brla3.conf (225 Bytes)
tegra19x-mb1-padvoltage-brla3.cfg (570 Bytes)
tegra19x-mb1-pinmux-brla3.cfg (26.2 KB)
tegra194-brla3.dtb (204.5 KB)

Hi @olivier.lutz

Actually I am asking for devkit situation. Since you said devkit can reproduce issue too, I would like to know if devkit actually has same synchronous error for all the monitors here.

Hi Wayne

Yes, the devkit has the same errors as our board.
See attached the serial logs of the devkit. Please note, that the devkit is flashed with our .config and .dtb.

log_no_display_devkit.txt (141.3 KB)
log_S24E450_devkit.txt (85.1 KB)
log_B233HU_devkit.txt (85.1 KB)
log_B193_devkit.txt (85.1 KB)

I just now retried it with the devkit .config provided by nvidia-sdk and now the devkit boots with screen attached (see
log_devkitcfg_S24E450.txt (191.8 KB)
), so the issue seems to be somwhere in our files. Do you have an idea where to start looking?

Thank you and best regards

What did you change in your dtb and config?

I cannot reproduce this issue on devkit.

Hi Wayne

I finally solved the problem. The issue was with the dts/dtb file
tegra194-brla3.dts (265.4 KB)
Apparently a new “bootloader-status” symbol was added in display@15200000, display@15210000 and display@15220000 in the JetPack 5.1 devkit dtb file which was missing in our dts file. I have now added

bootloader-status = “disabled”


status = “okay”

in those display entries and now the device boots with display attached.

Best regards

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