Screen auto brightness control and low ambient luminosity
The power saving option to use auto screen brightness works as expected for high ambient luminosity. The screen brightness automatically goes up when the ambient luminosity increases and goes down when ambient luminosity decreases.
However, if ambient luminosity is almost zero (night mode), the screen brightness also goes to 0. This behavior is not expected. The screen brightness should remain on some minimal level so the phone can be used.
Additionally, when auto brightness control is active and the screen brightness level becomes 0, it never goes up from this state regardless of ambient luminosity. This should be fixed.