Re: Brightness control does not work (static brightness level)

I have a brand new Dell Precision 5540 Laptop also with the 4K OLED display, Windows 10 Pro, build 1803, and also cannot adjust the brightness. I've literally done a clean installation of Windows 10 Pro, completely stock (I wish I had tested this on the Dell installed version of Windows 10 but I didn't get a chance to), I then installed all 33 downloads available for Windows 10 and my laptop,  it included every driver under the sun including:

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Version: 26.20.100.6911 ,A02

Last Updated Date: 27 Aug 2019

File Name: Intel-UHD-Graphics-630_KMFKH_WIN_26.20.100.6911_A02_01.EXE
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but no matter what, I cannot control the brightness. The indicator comes up, showing that it knows I'm trying to adjust the brightness and it thinks I'm doing it, but nothing.  I then grabbed version 26.20.100.7158  (from 9/5/2019) from Intel's site directly and I upgraded to that. Same exact result with the new driver, still not able to control brightness. 

I tried an older version of the Intel Graphics card driver mentioned on some forum, 25.xx something, but no luck there either.  So I don't know what to do now in terms of Windows.

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For Linux (I dual boot) I managed to get it working thanks to the info found here https://wiki.archlinux.org/index.php/Backlight#OLED_screen_brightness   you may find this interesting "Since the screen is OLED (which do not have physical backlights) and until brightness control for OLED screens is supported by the kernel, you may need to shim the ACPI backlight functions to update xrandr's "--backlight" option"

Basically OLED panels don't have physical back-lights. adjusting the brightness is more trickery to make it seem like it's doing that.  For Linux I used the ICC color profiles method to simulate the adjusting of brightness, not the shmming of the acpi backlight (whatever that means). Both methods did work though to simulate dimming the screen.  I imagine that for Windows, Dell uses a similar trick, something to intercept the system call to dim the screen and "simulate" the screen getting dimmer on the OLED panel, which is perfectly fine, but whatever program they use to simulate the screen dimming is obviously not stable or always working and I can't seem to find it on Dell's support site either, not one mention of OLED's in their drivers section.  They need a special "Monitor" driver instead of the standard "Generic PnP Monitor" driver,  like "Dell OLED Panel" driver.