We made a bit of progress here.
First, we followed Jun Sun’s step, it keep reporting as below:
[ 36.015] (EE) open /dev/fb0: No such file or directory
then xserver quit.
Second, we leave build 121 as it was by removing the newly created configuration file for fbdev. Then we run startx for once, it reports something from hisilicon went missing as before, and as expected we got /dev/fb0 showing up. Again I got the configuration for fddev back as Jun’s step, it seems works and now we can make xserver run in background. However, I still cannot make anything display on my LCD displayer.
So still stalled here. Need your help.