In my answer to my last question on this:
Why is the VOP (Video Output Processor) on the Rockchip RK3588 acting inaccessible?
I mentioned how that on my Rockchip RK3588 machine (a Firefly ITX-3588J board with attached hard disks), I have finally been able to prepare a version of "U-Boot" that merges the Rockchip DRM VOP driver with one of the newest versions of that bootloader program. But I am now at a point where I'm pretty stumped as to how to debug it.
What I have going on here now is that the driver mostly works: the bootloader starts up, and with the monitor attached, it cycles from the amber "no signal" light to the blue "signal" light, the screen backlight flips on and it says it's receiving a 1024x768 signal ... but it's blank. I've tried several things to coax something out including trying to force-write a test pattern to the frame buffer, but the screen remains black.
And yes, I've migrated all the driver code files and pretty much any relevant device tree entries I can think of in the FDT files from the BSP U-Boot to my new version, but it's still not working, and I'm pretty much now at the end of the line when it comes to ideas. Especially given I've pretty much learned everything I know about system-level programming from this one project which has been going on and off over the past year. I've also tried to ask a couple of sites about this at other stages without responses, and I have long struggled to find a place with both high activity and where it'd likely be on topic.
What do you suggest?