We want to upgrade our current system from an Colibri iMX7D to a more powerfull Colibri iMX8DX. With the iMX7D, everything works as expected.
For a first test I have build the tdx-reference-multimedia-image and added the customized device tree for our display.
The built image boots, shows the framebuffer console and starts the test application Qt5_CinematicExperience. As soon als the video starts playing, the image is heavily disturbed. When I start glmark2-es2-wayland, the display also flickers.
When I switch to a framebuffer console, the flickering stops immediatly. Also, when only the desktop or a weston-terminal is running, the display does not show any disturbances.
For reference, I also tested with the prebuilt Torizon, that starts chromium. Chromium also shows the artifacts.
I already considered EMC and tried to move the cable further away. I also added a shielding foil around the cable and the CPU module. There is no change in any way to the behaviour.
Since the RGB interface has a voltage swing of 3.3V, the EMI has to be rather large, to cause an error. From the image distortion, the affected signal must be the clock or the hsync signal. I mesuered both signals but could not see any problems with the signal quality.
From this I currently assume, the signals are already distorted, when leaving the module.
On monday, I hope I will get hands on a second module and see, if the problem is the same.