I remembered i.MX6 L3.0.35 supported dual LVDS display to set kernel parameter such as ldb=dul0.
Then I tried this for KK4.4.3 but some of them were ignored.
c.f. u-boot=> setenv mmcargs .... ldb=dul0
The results were:
ldb=dul1 OK #dual (same output to 2 panels)
ldb=sep Fail(same as dul1) #serarate
ldb=spl1 Fail(same as dul1) #split (2 ports for 1 panel)
Is this parameter still valid/alive?