I tested the kernel upgrade with a couple of displays that I have at hand. The first one, a generic unbranded DSI display for Raspberry, and it worked great. Curiously a Waveshare display for RPi, seems that doesn’t even turn on the backlight. However this same displays works well with Rock Pi 4 plus, after enable raspberrypi-7 overlay.
Could you give me some advice on how to debud this?
@gacktex suggests you should disable touch so you don’t get i2c stuck.
Today i received two 7" LCD from different makers, both with FT2506, one (the cheapest) worked, and the other have trouble with the backlight, even with touch disabled. But both touch works fine.
@gacktex, in your post you comment this " GPIO3-C7 of the MIPI-DSI interface is not powered on by default, resulting in no response from the slave. . . ."
Can you elaborate on what you did , maybe this can help?