I moved the OpenChrome DRM development into drm-next-4.20 branch more than a week ago, but I discovered that when OpenChrome DRM is being used, it can no longer boot the OS.
The reason for this is due to a strange bug introduced by I2C bus subsystem device driver between Linux 4.18 rc4 and rc7. The matter was not resolved by upgrading to Linux 4.19 rc1. I have tried to find the offending commit of I2C bus subsystem, but I am not able to find the bad commit so far. I contacted the I2C bus subsystem maintainer, but he denied that “core” I2C bus subsystem device driver has changed recently. Generally speaking, the I2C bus subsystem maintainer did not show much interest in the issue when I reported the issue to him directly via e-mail. I guess I will have to go bisect the issue myself.