Hello. I have combination of:
- iMX8MMini: NXP i.MX 8M Mini / Nano - Verdin System on Module V 1.1A
- Verdin Dev Board: Verdin Development Board with HDMI Adapter V 1.1B
- DSI to HDMI adapter Verdin DSI to HDMI Adapter ) Rev 1.1
- Waveshare 7inch HDMI LCD (H) 1024×600: https://www.waveshare.com/wiki/7inch_HDMI_LCD_(H)_(with_case)
- 12V power supply
I have flashed tdx-reference-multimedia-image and i have problems with displaying image on 7inch screen. It works - displays image - on my Dell U2414H monitor (though screen is greenish/pinkish but i can see demo, animations, text, etc., so i guess it is related to HDMI cable/standard?). But when i use the same HDMI cable to connect iMX8MMini+DevBoard+Adapter to 7 inch screen it doesnt show any image (other HDMI cable that works with different boards yields the same result - no video).
It works if i power LCD via PC USB hub, turn board on, let it initialize and then touch tip of USB-c cable (from PC USB hub) to case of USB connector (X33 / X66) or even RS232/USB-H (X51 / X53). Image shows up with corrent colours.
So my guess it has something to do with common electrical ground? All devices (my PC, screens, USB hub, dev board) are using one power sorce - same power strip.
dmesg related to screen:
dmesg | grep lt8 [ 2.747251] lt8912 3-0048: "1024x600": 60 49000 1024 1029 1042 1312 600 602 605 622 0x48 0x5 [ 2.751494] lt8912 3-0048: LT8912 ID: 12, b2
Another case: when i power LCD screen by connecting LCD screen via dev board USB - it works for a moment (i can sometimes see booting logs but then its all black again - backlight on). Usualy after powering up red led on dsi adapter blink → sometimes logs show up on screen, sometimes not → red led blinks again and screen stays black + backlight on.
I have another 7inch screen and it behaves the same.
Maybe someone had already encountered such problem before?
Is it related to electronics / jumpers configuration somehow? Or maybe it has something to do with driver/ initialization/ configuration?