BeagleBone AI 64 Display issues

I want to make sure I am not totally missing something. I just got my BeagleBone AI 64, and all works well when I have it tethered to my laptop but I would like to get it to work with a monitor and keyboard. I have a display port to HDMI cable and have tried it with multiple monitors and a TV but I do not get a signal out. I have tested the monitor and know the TV is fine as well. I have also tried 2 different cables from BestBuy. Is there anything I need to do to enable the display port or does it sound like the board may have issues?

Hello,

I have a display port cable that will fit the BBAI-64 and it leads, the other end, to a full-sized display port connection.

I will try this one out. I know sometimes the cabling does not fully function in some devicesā€¦

  1. For instanceā€¦
    a. My USB-C to HDMI cable does not currently work w/ the monitor I have on the desktop.
    b. There are other chipsets that Linux has not implemented, i.e. I am sure of it.

  2. I will test the cable and report back but I do not think I have the cable you are discussing.

Oh! Try to add some power 5v 3A to the power connector barrel jack on the BBAI-64. It may be an actual constraint of power needing to be given.

Seth

P.S. Anyway, I will have some time to test soon.

GOOD NEWS

I tested the Mini DP to the DP cable. It works!

OTHER NEWS

I think Linux has a way w/ the files to handle such a build of the chipset on your device.

  1. First, find out what is built into the cable.
  2. Second, if it shows a type and build, there may be a Linux command like modprobe to handle such a ā€œbuilt inā€ driver.
  3. Third, while using ssh to handle your BBAI-64, run the commands to see about what is attached.
    a. Maybe try, but you know me as not quite sure just yet, cd /sys/devices/platform/bus@100000/4a00000.dss/drm/card0/card0-DP-1/ and then look in status?
    b. Orā€¦try this command: find /sys/devices -name "edid" . I found that command and these ideas online at xrandr - Bash list all display output ports - Unix & Linux Stack Exchange

So, @hoffman.jonā€¦

I think what exactly is this idea.

  • Linux, if installed via the compilation of your image, has mechanisms to install drivers via modprobe.
  • Also, there is something called a LKM. I am sure you are aware of this mechanism in Linux.
  • Anyway, here: Introduction to Linux Loadable Kernel Modules

That link will guide you, if already installed via a module, on how to build it but I think it may brake your system, i.e. as LKMs are infamous for it.

Seth

P.S. I am sure there are other ways of doing things. Linux is full of surprises.

Are you using an ā€˜activeā€™ Display Port adapter?

Passive ones donā€™t work with the design of this sbc.

Regards

2 Likes

@RobertCNelson thank you for the reply, my guess is that is what it is. I ordered a new cable off of Amazon that is ā€˜Activeā€™ and it should be here Thursday.

@RobertCNelson That was the problem, just received the new cable and everything works perfectly. Thank you again for the reply.

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I also have a problem with the Display Port cable.
Before I bought the Beagle AI-64 board I thought it was as easy as the HDMI display. However, I cannot make the screen visible.
The choice of Display Port replace HDMI was a mistake, why donā€™t you give a simple and common HDMI port?

Hi @Kevin_Nguyen2022 sorry, you need an ā€œactiveā€ adapterā€¦

Such as: https://www.amazon.com/gp/product/B089GF8M87/

The TDA4 processor on the BeagleBone AI has a native DisplayPort interface, so no encoder chips are required (like BeagleBone Black ā€œframerā€). Where we messed up, thereā€™s an addendum to the DisplayPort spec to work with ā€œpassiveā€ devices, hence the really cheap DisplayPort > HDMI adapters donā€™t work, you need an ā€œActiveā€ oneā€¦

Regards,

I have the adapter linked and have not managed to get it to output to a display on the BBAI-64. I havenā€™t spent time diagnosing it and Iā€™ve only tried one monitor but my initial impression has been that it doesnā€™t work in my testing.

I have a question, can any DisplayPort to HDMI converter cable of Active type be used?
Please let us know of some alternative equivalents to recommended cables sold on Amazon.

This model does work, just got it a few days ago.

www.amazon.com/dp/B01FM51O0W

I have purchased several others that did NOT work so its pretty much a learning experience.

@Kevin_Nguyen2022 I bought this one, and can verify that it works great:

Thanks for review.

Hi. I tried a Mini DP to DP cable, and it kinda works but the screen is somewhat unstable. Some parts of the screen, specially the bottom half, flicker, actually, they move a lot, for example, it may sound funny, the dog on the background jumps to the left, past the middle of the screen, and gets back again.

Did anyone notice a similar issue? Iā€™m using a 4K monitor.

I had the same problem. It was only a problem at 4K resolution, no problem at FHD.
The screen wasnā€™t moving, but it was constantly flickering.

I compared a miniDP 1.2 to HDMI 1.4 cable to a miniDP 1.4 to HDMI 2.0 cable.

The miniDP 1.2 cable had problems and the miniDP 1.4 cable had no problems.

cdns-mhdp8546 a000000.dp-bridge: Failed to read receiver capabilities

Only the DP 1.2 to HDMI 1.4 cable had that problem and I couldnā€™t fix it so I returned it.

If youā€™re having miniDP issues, check your cable version.

I compared only one companyā€™s products (ā€œCODEWAYā€ in korea). If it works with miniDP 1.2 to HDMI 1.4, it may be a problem with the product, so please check the version of the miniDP to HDMI cable.

Oh, and of course, no matter what cable I used, I had problems at 4K resolution.

Thank you.

Iā€™m using a miniDP to DP cable (1.4), and the only resolution available is 4K. Iā€™ve tried to add other modes via xrandr (with mode lines from both cvt and gft for 1920x1080 and 2560x1440 both at 30Hz and 60Hz) but it fails to change the resolution.

To be honest, I mostly use the board via ssh, but Iā€™d like to have a working display option anyway. Maybe Iā€™ll try an HDMI connection.

I also has the flickering problem, with StarTech Active mDP 1.4 to HDMI 2.0 (MDP2HD4K60S) on a 4K display.

I doubt it is entirely the converter cable issue. Below are some findings:

  • With native mDP-DP: the monitor reported input signal is 4K30Hz, no flickering, however you will see tearing issue when moving windows around.

  • With the active mDP to HDMI: the monitor reported input signal is 4K60Hz, this has flickering issue. One thing I notice, the flicker issue seems to only happen in the desktop environment. There is no flicker issue when running a graphic app e.g. sudo rgx_triangle_test -p or sudo rgx_blit_test. And to make the flickering worse, run sudo rgx_triangle_test -offscr.

  • xrandr does not seems to work.

I am running BBAI64 with the factory installed image: ā€œBeagleBoard.org Debian Bullseye Xfce Image 2022-01-14ā€. Not sure if this is fixed with later releases (I hope it is).

Yes, as I said before, I tried xrandr and it didnā€™t work. Anyway, this info you added about graphic apps not flickering is very interesting. Iā€™m about to try an HDMI connection, but didnā€™t have the time yet (in Canada one must seize every free day of summer outdoors :D).

I have an mDP to mDP direct cable to my monitor but am only getting 1024x768 default resolution. xandr doesnā€™t help. Any suggestions?