hardware hack Legacy kernel 2k HDMI LCD

[prenex]

Hello everybody.

 

I am trying to build an DIY headset from scratch and I originally planning to use some armbian OS for its SBC at its heart of the device (like an orange pi, or something maybe a bit stronger who knows - I happily accept recommendations). For the headset it is necessary to have proper opengl support with hardware rendering capabilities and also good to have video acceleration maybe so I think the legacy kernel fits the purpose best.

 

PROBLEM: I tried to plug in the HDMI display - it does not work.

 

Details:

 

The display is seemingly not working when attached to the HDMI port. I see some led flashing so I think some handshaking is in progress, but it never finishes it. It works on a regular PC and have very high DPI density and high resolution. I have found that I might need to fuss-around a bit with fex / bin trickery, but I am unsure. I have also heard that mainline kernels have "better support" for custom resolutions and stuff like that, but I am unsure if hardware GPU / GLES2 acceleration would work properly for it.

 

This is the display I am trying to use:

https://www.aliexpress.com/item/5-5inch-2560-1440-2K-LCD-Screen-3D-VR-Headset-Glass-Virtual-Reality-HDMI-to-MIPI/32813542714.html?spm=2114.search0104.3.22.53a94c17uvnHzK&ws_ab_test=searchweb0_0,searchweb201602_4_10152_10151_10065_10068_10344_5012917_10342_10343_10340_10341_10696_5012717_10084_10083_10618_10304_10307_10820_10821_5012817_5013017_10302_10059_100031_10103_10624_10623_10622_10621_10620,searchweb201603_51,ppcSwitch_5&algo_expid=3b6cb23a-4bae-406a-b19d-9a3865f2a47d-3&algo_pvid=3b6cb23a-4bae-406a-b19d-9a3865f2a47d&priceBeautifyAB=0

 

Also currently I am just using my "Orange Pi PC plus" at home for my experiments. I am not sure however if there is a better SBC for building the headset. What I need is support for the LCD above through HDMI and some processing power to render 3D graphics. Positioning and mapping will be offloaded to custom electronics so the SBC mostly will only render to the screen of the smart helmet if things go as I am planning so the Opi could be actually enough for my performance needs maybe.

 

What I am unsure about:

- Do I need to configure something in software for this HDMI LCD to work with armbian?

- Or did I ran into my orange pi not having enough hardware capabilities to support this LCD throuh HDMI (not supporting some HDMI protocols maybe or whatever?)

- Do I need to compile my own armbian kernel to modify configuration of the hdmi resolutions?

- Or can I edit some bin/fex/whatever files?

- Where are things documented or written about this topic if there is any such?

- Do any of you advice a better device than my orange pi?

- Can anyone explain what happens and how HDMI works under the hood or how to understand it? To be honest I originally thought it is some easy plug&play stuff, but now I see there are "timings", config values, different versions of the HDMI protocol ad stuff like that I am not completely understanding yet.

 

Best regards,

prenex

[prenex]

PS.: The display itself works on a PC and I will try if it works with a raspbian running on a raspberry pi 3b or not. I do not have or plan to have those hw/sw in the first place as armbian was great so far for everything. Quite a stable system so far.