I have a HP 450G4 laptop. It originally came with a (horrible) TN screen. I have mojave 10.14.6 and brightness was working 100% on the TN panel.
So I changed the TN panel for a compatible IPS panel I just bought, an AUO B156HAN01.1.
Now, the display only works at maximum brightness level. Any other level causes the screen to go black, or to flicker like every 2 seconds (that is, black screen generally with occasional PWM flickers with the content every 2 seconds)...
Brightness problems after upgrading screen from TN to IPS: Brightness only works AFTER sleep
So I changed the TN panel for a compatible IPS panel I just bought, an AUO B156HAN01.1.
Now, the display only works at maximum brightness level. Any other level causes the screen to go black, or to flicker like every 2 seconds (that is, black screen generally with occasional PWM flickers with the content every 2 seconds)...
Brightness problems after upgrading screen from TN to IPS: Brightness only works AFTER sleep