STM32MP257F-DK HDMI output to 9.3" waveshare display at native res

[Jled]

Hi there I have a STM32MP257f-DK board running the latest Linux, and I’m trying to output to a waveshare 9.3” HDMI display at its native resolution. 1600x600

I can output to it at 1920x1080. and I can output to the display from my Mac at it’s native 1600x600.

 

I see a slight flicker when I try send video then black. then the display goes to sleep. So the display is losing sync.

linux reports the output is working, but it seems it’s something to do with the ADZ7xx chip.

any ideas?