Gamma and brightness control is not available on Raspberry 4 & 5

Since I am using a Raspberry PI 4 to serve Homeassistant on a 24″ touchscreen, I was eager to use something like Redshift or F.Lux to adapt the gamma and brightness settings of my screen to my timezone, i.e., to dim and reduce the blue light at night.

Unfortunately, I had to learn that this is not possible on an Rasperry 4 or 5, since this seems to be not implemented within the firmware. Raspberry 3 seems to be not affected, but due to a lack of hardware I was not able to confirm this.

Primary source: https://github.com/raspberrypi/firmware/issues/1274. Sadly, the issue was locked and there was no update since 2022.

I did some digging and read about KMS, FKMS and a switch (Either dtoverlay=vc4-fkms-v3d or “dtoverlay=vc4-kms-v3d”) to be placed in /boot/firmware/config.txt, but none of this was successful.

These findings were made an 14.04.2025 on a Raspberry 4:

uname -a

Linux raspberrypi 6.12.20+rpt-rpi-v8 #1 SMP PREEMPT Debian 1:6.12.20-1+rpt1~bpo12+1 (2025-03-19) aarch64 GNU/Linux

Also, rpi-update was conducted:

max@raspberrypi:~$ sudo rpi-update
*** Raspberry Pi firmware updater by Hexxeh, enhanced by AndrewS and Dom
*** Performing self-update
*** Relaunching after update
*** Raspberry Pi firmware updater by Hexxeh, enhanced by AndrewS and Dom
FW_REV:0a0b3671d5fd313983ea584c6067836e5143eb3b
BOOTLOADER_REV:816bf7c594a4c117ab2815f443ad3d535be475a6
*** We're running for the first time
*** Backing up files (this will take a few minutes)
*** Backing up firmware
*** Backing up modules 6.1.0-rpi7-rpi-v8
WANT_32BIT:0 WANT_64BIT:1 WANT_64BIT_RT:0 WANT_PI4:1 WANT_PI5:1

#

WARNING: This update bumps to rpi-6.12.y linux tree
See discussions at:
https://forums.raspberrypi.com/viewtopic.php?t=379745

#

Would you like to proceed? (y/N)
Downloading bootloader tools
Downloading bootloader images
*** Downloading specific firmware revision (this will take a few minutes)
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0
100 151M 100 151M 0 0 3985k 0 0:00:39 0:00:39 --:--:-- 4336k
*** PREPARING EEPROM UPDATES ***

BOOTLOADER: update available
CURRENT: Thu 3 Sep 12:11:43 UTC 2020 (1599135103)
LATEST: Tue 11 Feb 17:00:13 UTC 2025 (1739293213)
RELEASE: latest (/usr/lib/firmware/raspberrypi/bootloader-2711/latest)
Use raspi-config to change the release.

VL805_FW: Dedicated VL805 EEPROM
VL805: up to date
CURRENT: 000138c0
LATEST: 000138c0
CURRENT: Thu 3 Sep 12:11:43 UTC 2020 (1599135103)
UPDATE: Tue 11 Feb 17:00:13 UTC 2025 (1739293213)
BOOTFS: /boot/firmware
'/tmp/tmp.P04Uq1QHWm' -> '/boot/firmware/pieeprom.upd'
Copying recovery.bin to /boot/firmware for EEPROM update

EEPROM updates pending. Please reboot to apply the update.
To cancel a pending update run "sudo rpi-eeprom-update -r".
*** Updating firmware
*** Updating kernel modules
*** depmod 6.12.22-v8-16k+
*** depmod 6.12.22-v8+
*** Updating VideoCore libraries
*** Running ldconfig
*** Storing current firmware revision
*** Deleting downloaded files
*** Syncing changes to disk
*** If no errors appeared, your firmware was successfully updated to 0a0b3671d5fd313983ea584c6067836e5143eb3

Sources for further investigations