Jetson Orin Nano 8-inch Display Compatibility Issue (Requires >60Hz)

Robotics & Edge Computing Jetson & Embedded Systems Jetson Orin Nano
1

I’m unsure which small 8-inch display I should purchase to ensure compatibility with the Jetson Orin Nano. It appears that displays running at exactly 60Hz aren’t supported, and the device only works with refresh rates above 60Hz. Could anyone recommend an appropriate 8-inch monitor that meets these requirements?

2

I don’t know which display to use, but some information might be useful to you:

  • The display must be either HDMI or DisplayPort. The reason is that these have a wire called the “DDC” wire, and that wire allows the monitor to self-describe through an EDID query. Most desktop PC drivers allow alternate methods of configuring for a display, but Jetsons have a driver that requires this information to configure (otherwise it probably goes to an incompatible default mode).
  • VGA adapters, USB video, and analog DVI are not compatible (also, keep in mind that we are really using EDID2, and Jetsons do not seem to be compatible with the very short-lived EDID version that VGA monitors sometimes had).
  • Each monitor has a log you can use to find more information on a specific monitor. There is a “DISPLAY” environment variable which ties a given desktop to software, including logging. If you are in the X11 server GUI, then it is easy to find out with “echo $DISPLAY”. Most of the time this shows as “:0”, in which case the context is “0”; the log would then be “/var/log/Xorg.0.log”. If you have two monitors, then one might be Xorg.0.log and the other Xorg.1.log (assuming they are separate; they could both be combined into Xorg.0.log or Xorg.1.log). That log file is important, and you may have found one already that says it is unsupported.
  • You can add this to Section "Device in “/etc/X11/xorg.conf” to get increased details on what the driver thinks of the EDID mode:
Section "Device"
    Option "ModeDebug"

That said, this doesn’t do a lot to find a monitor that works, it is basically a way to diagnose what goes on with a given monitor. All of the above is more or less about the topic of “modelines”. A modeline is a set of timings for a scan line on a monitor. I mention this because there are many many monitors with a 60 Hz scan rate which are fully supported. If a particular 60 Hz monitor is not supported, and if it is HDMI or DisplayPort (or digital DVI), then the failure will be due to one of the other timings in the compatible modelines. If you avoid 60 Hz monitors, then you are missing out on a lot of monitors.

Unfortunately, I don’t know a way of providing a list of valid monitors without actually trying them. You might find 1080p at 60 Hz supported, but not a 480p at 60 Hz. If there is a list of compatible monitor modes I don’t know, but this would be quite useful; that list would have to combine several parameters together as a whole rather than simply stating 60 Hz works or does not.

3

I’m only planning to use HDMI and DisplayPort, not VGA. The monitor I’m currently using supports both HDMI and DP, and I’ve successfully connected it to the Jetson Orin Nano using either interface. This monitor is a 4K display running at 60 Hz. However, when I try connecting other monitors that are 1080p with a 100 Hz refresh rate, they fail to work. I even tried a small display and ran into the same problem. Could this issue be related to the Jetson’s DisplayPort setup—meaning it might only work with displays that support DP?

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I think it should work on both DisplayPort and HDMI. Sometimes, if one is using an adapter, it will fail for reasons related to the adapter. However, both DisplayPort and HDMI contain the necessary configuration data and so both should work.

Note that the Jetson might not support some specific monitor setting, e.g., it might not support 1080p with some specific 100 Hz refresh, but it most certain should support some more common mode, e.g., 1080p at 60 Hz. If you were to make that adjustment that I mentioned above for ModeDebug, and then get a lot file for a specific monitor, then you could post the log file here. That file would actually list what the driver says about every mode the monitor is capable of, and whether a mode is rejected or accepted. The log might also tell us it is something else and not the monitor modes which are the cause. Without that log this will just be a statistical guessing game. Note that the adjustment to add ModeDebug to logging just increases details; however, we don’t even have a less detailed log yet.

Although the log won’t tell us about “all” modes, it will tell us about “all modes of a given monitor that is currently plugged in and what the driver thinks about it”.

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