NVIDIA Controller SDR Brightness setting does not change it fully

[rajkosto]

The slider in Windows HD Color settings does not move (even after restarting that settings applet) when this is changed via ColorControl, and I wouldn't mind it if it was just cosmetic, however, one IMPORTANT program that uses the setting's value directly somehow is Chrome, especially it's SDR Video rendering when in HDR mode (and when RTX Video HDR is off).

In short, changing the SDR brightness in HDR mode via NVIDIA Controller in ColorControl does not affect SDR video's brightness in Chrome, they will always be at the brightness the actual Windows SDR Brightness value, moving the slider manually does affect the video brightness.

Another program not affected by the SDR Brightness in ColorControl but is affected by the one in Windows HD Color settings is the Discord Windows client. It only changes its brightness on minimize/maximize but only if the slider is manually moved in Windows HD Color settings, not if ColorControl changes it.

Seems the cause is Chromium manually retrieving the SDR white level with
https://chromium.googlesource.com/chromium/src/+/c71f15ab1ace78c7efeeeda9f8552b4af9db2877/ui/display/win/screen_win.cc GetMonitorSDRWhiteLevel function, and rendering everything in HDR using that as a scale