About the “reComputer AI Lab” Category

reComputer AI Lab
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reComputer AI Lab is a one-stop development platform for reComputer edge hardware, enabling developers to deploy AI models in just two steps and drastically lowering the barrier to edge AI development.

This category is for discussing usage, troubleshooting, deployment cases, and feature requests.

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Hi admin, I can’t create a new topic, so please let me post as a comment in this post.

I am currently using a Seeed reComputer Mini J501 kit with the official Seeed JetPack 6.2.1 image:

mfi_recomputer-mini-agx-orin-j501-6.2.1-36.4.3-2026-02-05.tar.gz

Hardware:

  • Seeed reComputer Mini J501

  • Jetson AGX Orin module

  • HDMI monitor connected directly

  • Serial debug console via ttyTCU0 working normally

Problem:
The system boots successfully, but the HDMI monitor remains completely black.

Initially during boot I observed repeated DRM errors such as:

[drm:nv_drm_atomic_commit [nvidia_drm]] ERROR [nvidia-drm] Flip event timeout on head 0
[drm:nv_drm_atomic_commit [nvidia_drm]] ERROR [nvidia-drm] Failed to apply atomic modeset

and also:

[nvidia-drm] Failed to grab modeset ownership

After modifying kernel parameters, the flip timeout errors disappeared, but HDMI output is still black.

Current kernel parameters:

nvidia-drm.modeset=1
nvidia-drm.fbdev=0

I also disabled Wayland:

WaylandEnable=false

and switched from gdm3 to lightdm + XFCE, but HDMI is still black.

Important observations:

  1. HDMI monitor is detected correctly

The following DRM node exists:

/sys/class/drm/card1-HDMI-A-1

Status:

connected

Supported modes include:

  • 2560x1440

  • 1920x1080

  • etc.

EDID can be read successfully.

  1. DRM drivers load successfully

lsmod shows:

  • nvidia_drm

  • tegra_drm

  • drm_kms_helper

  1. Framebuffer exists

cat /proc/fb

returns:

0 simple

fbset -i shows:

mode “2560x1440”

  1. Framebuffer write test succeeds

I tested:

sudo fbi -T 1 -d /dev/fb0 /usr/share/backgrounds/warty-final-ubuntu.png

No error is reported, but the HDMI monitor still stays black.

  1. Xorg starts but exits

startx output:

xinit: connection to X server lost
Server terminated successfully (0)
Couldn’t get a file descriptor referring to the console.

  1. Current suspicion

It looks like:

  • simplefb is active

  • framebuffer memory exists

  • HDMI EDID works

  • but the actual display scanout/display plane may not be active.

Questions:

  1. Is this a known issue on reComputer Mini J501 with JetPack 6.2.1?

  2. Is there a recommended DRM/KMS configuration for stable HDMI output?

  3. Should simplefb be disabled?

  4. Is there any known conflict between:

    • simplefb

    • tegra_drm

    • nvidia_drm

  5. Is there a recommended extlinux.conf configuration for HDMI stability?

Any help or recommended configuration would be greatly appreciated.

Thank you.

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I flashed the official Seeed MFI image for reComputer Mini AGX Orin J501, JetPack 6.2.1 / L4T R36.4.4.

HDMI is now detected:

  • /sys/class/drm/card1-HDMI-A-1/status = connected

  • EDID is readable

  • xrandr shows HDMI-0 connected primary 2560x1440

But the screen remains black, and kernel logs show:

  • [drm:nv_drm_atomic_commit] Flip event timeout on head 0

  • tegra-mc ... nvdisplayr: secure read ... EMEM address decode error

  • arm-smmu ... Unhandled context fault

I checked the MFI flash.idx, and the display/DCE firmware is flashed from:
display-t234-dce_with_tegra234-j501x-0000+p3701-0004-recomputer-mini_with_odm_overlay.dtb_with_dce_overlay_aligned_blob_w_bin_sigheader.bin.encrypt

Is there a known issue with the DCE/display overlay loading order or DCB config for J501 + AGX Orin 32GB on R36.4.4?