Screen brightness is super low after upgrade to 24.04.1 LTS

Question

After upgrading from Ubuntu Desktop 22.04 LTS to Ubuntu Desktop 24.04.1 LTS, I found out one of monitors to have low brightness. I couldn't find any control to change the brightness and when I googled for solutions, nothing helped me. Here are some outputs:

lspci -k | grep -EA3 'VGA|3D|Display':

00:02.0 VGA compatible controller: Intel Corporation CometLake-S GT2 [UHD Graphics 630] (rev 03)
    DeviceName: Onboard - Video
    Subsystem: Dell CometLake-S GT2 [UHD Graphics 630]
    Kernel driver in use: i915

neofetch:

OS: Ubuntu 24.04.1 LTS x86_64 
Host: OptiPlex 7480 AIO 
Kernel: 6.8.0-41-generic 
Uptime: 15 mins 
Packages: 2244 (dpkg), 22 (snap) 
Shell: bash 5.2.21 
Resolution: 1920x1080 
DE: GNOME 46.0 
WM: Mutter 
WM Theme: Adwaita 
Theme: Yaru-blue-dark [GTK2/3] 
Icons: Yaru-blue [GTK2/3] 
Terminal: gnome-terminal 
CPU: Intel i5-10500 (12) @ 4.500GHz 
GPU: Intel CometLake-S GT2 [UHD Graphics 63 
Memory: 3298MiB / 15677MiB

sudo ubuntu-drivers list returns nothing, while sudo ubuntu-drivers install returns

All the available drivers are already installed.

ls -al /sys/class/backlight returns

total 0
drwxr-xr-x  2 root root 0 Sep  4 11:41 .
drwxr-xr-x 85 root root 0 Sep  4 11:22 ..

xrandr | grep " connected" | cut -f1 -d " ":

DP-1
HDMI-2

xrandr --output DP-1 --brightness 1 and xrandr --output HDMI-2 --brightness 1 does nothing.

I tried the hack with Brightness controller, editing grub, Secure Boot DISABLED.

I am more than welcome for any advice.

I have also had to do a fresh install of Ubuntu Desktop, because upgrade from Ubuntu 22.04 LTS failed.

Update with Hannu's response: After implementing the setdbr function I get:

martin@dell:~$ setdbr
Current displays, numbered:
     1  DP-1 connected 1920x1080+1920+0 (normal left inverted right x axis y axis) 510mm x 290mm
     2  HDMI-2 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 520mm x 290mm

And whatever I type, nothing changes. I tried setdbr 1 1.0, setdbr 2 1, setdrb 2 0, setdbr 1 0

UPDATE 2: I tried to turn on the night light and play with the intensity and both displays reacted. Thank to this I think the problem won't be Kernel-related and there is still some setting missing.

I am also missing the brightness slider in top right menu, maybe this could help?

UPDATE 3: output of lspci:

00:00.0 Host bridge: Intel Corporation Comet Lake-S 6c Host Bridge/DRAM Controller (rev 03)
00:02.0 VGA compatible controller: Intel Corporation CometLake-S GT2 [UHD Graphics 630] (rev 03)
00:08.0 System peripheral: Intel Corporation Xeon E3-1200 v5/v6 / E3-1500 v5 / 6th/7th/8th Gen Core Processor Gaussian Mixture Model
00:12.0 Signal processing controller: Intel Corporation Comet Lake PCH Thermal Controller
00:14.0 USB controller: Intel Corporation Comet Lake USB 3.1 xHCI Host Controller
00:14.2 RAM memory: Intel Corporation Comet Lake PCH Shared SRAM
00:14.3 Network controller: Intel Corporation Comet Lake PCH CNVi WiFi
00:16.0 Communication controller: Intel Corporation Comet Lake HECI Controller
00:16.3 Serial controller: Intel Corporation Comet Lake Keyboard and Text (KT) Redirection
00:17.0 SATA controller: Intel Corporation Comet Lake SATA AHCI Controller
00:1c.0 PCI bridge: Intel Corporation Comet Lake PCIe Port #6 (rev f0)
00:1d.0 PCI bridge: Intel Corporation Comet Lake PCI Express Root Port #9 (rev f0)
00:1f.0 ISA bridge: Intel Corporation Q470 Chipset LPC/eSPI Controller
00:1f.3 Audio device: Intel Corporation Comet Lake PCH cAVS
00:1f.4 SMBus: Intel Corporation Comet Lake PCH SMBus Controller
00:1f.5 Serial bus controller: Intel Corporation Comet Lake PCH SPI Controller
00:1f.6 Ethernet controller: Intel Corporation Ethernet Connection (11) I219-LM
01:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. RTS525A PCI Express Card Reader (rev 01)
02:00.0 Non-Volatile memory controller: Micron/Crucial Technology P1 NVMe PCIe SSD[Frampton] (rev 03)

ls -al /sys/class/backlight returns nothing.

score 1 · Answer 1 · answered Sep 17 '24 at 23:57

I have the same problem after upgrading to Ubuntu 24.04.1 using a laptop (NVIDIA driver) + additional monitor display

Random dim light on laptop not easily fixed because the brightness control (top right menu of laptop) is unreadable
missing the brightness slider in top right menu of laptop

I Recover by closing the laptop to force display on secondary monitor

ThankYee · Answer 2 · 2024-10-18T05:16:10.667

The ddcutil is perfect for this, but not all monitors are supported.

To set my brightness to 100% on my desktop monitor: ddcutil setvcp 10 100

To set it to 1%: ddcutil setvcp 10 1

My monitor is a DELL S3221QS.

Laptop screens usually do not expose DDC/CI interfaces, so I run the following command to dim my laptop screen and my external monitor in the evening: sudo bash -c "ddcutil setvcp 10 1; echo 4800 > /sys/class/backlight/intel_backlight/brightness"

Hannu · Answer 3 · 2024-09-11T20:13:43.053

Place this in e.g. your $HOME/.bashrc to have it defined every time you start a terminal (bash-prompt).

function setdbr () 
{ 
    if [ "$1" == "" ]; then
        echo "Current displays, numbered:";
        xrandr | sed -nre 's/^([^ ]+ connected.*)$/\1/p' | cat -n;
    else
        xrandr --output    \
        $( xrandr          \
           | sed -nre 's/^([^ ]+) connected.*$/\1/p' \
           | head -n $1    \
           | tail -n 1     \
        )                  \
        --brightness $2;
    fi
}

Then

$ setdbr
will list all displays you have active.

$ setdbr 1 1.0
will set the first listed display brightness to 100%
... and
$ setdbr 1 0.5
... reduce it to 50%

Numbers higher than 1.0 are accepted, but does what you'd expect; i.e, 1.5 is something near 150% brightness, 10.0 might be 1000% ;-)

Tested on nVidia driven display on 24.04 and 20.04
Note: xrandr is installed by default.

score 0 · Answer 4 · answered Sep 12 '24 at 14:49

This might be some Grapics-driver's compatibility issue with your Kernel. Mine has similar issue of the brightness. My keyboard brightness controlls are not working. And nor i have any brightness controls in my settings menu after installing latest ubuntu upgrades.

Though, Ubuntu works fine and I have to connect to charger to get brightness high(max) otherwise its too dim.

hope you'll find some usefulness in this answer.

WinEunuuchs2Unix · Answer 5 · 2024-09-17T22:40:49.257

OptiPlex 7460 AIO Ubuntu compatibility

Your machine is tested to be compatible with Ubuntu 18.04 LTS. Also note the Kernel version it was tested with. So it might work to use an older kernel version as indicated in another post.

Compatibility test results from first link shown below:

Ubuntu 18.04 LTS 64 Bit

Pre-installed in some regions with a custom Ubuntu image that takes advantage of the system’s hardware features and may include additional software. Standard images of Ubuntu may not work well, or at all.

Kernel

This system was tested with 18.04 LTS, running the 5.0.0-1043-oem-osp1 kernel.

OptiPlex 7460 AIO: Resolving a problem adjusting the LCD brightness

Summary: This article takes you through steps on how to resolve an issue on the OptiPlex 7460 AIO desktop where you cannot adjust the screen brightness.

Generic Software Brightness Adjustment

xrandr --output DP-1 --brightness 1 will do nothing because that is where brightness already is at.

xrandr --output DP-1 --brightness 2 will double your brightness which is closer to what you desire.

if double brightness is too bright you can use xrandr --output DP-1 --brightness 1.5 for a 50% increase.

This is a software solution though and not ideal. A hardware solution is preferred.

score 0 · Answer 6 · answered Nov 08 '24 at 18:52

To add to the answer from @ThankYee, I first used ddcutil getvcp ALL to list my external monitor features. The relevant line in the output was:

VCP code 0x10 (Brightness                    ): current value = 12228, max value = 65535

I noted that the feature code for brightness is 0x10 (i.e 10). I have two Apple Thunderbolt displays, so I used the following commands to set the brightness to 100%:

ddcutil --display 1 setvcp 10 65535
ddcutil --display 2 setvcp 10 65535

The numbering of the displays came from ddcutil detect.

score -1 · Answer 7 · answered Sep 12 '24 at 15:35

-1

I too got similar situation. now it fixed (not a bug) by opinions of ChatGPT. go to settings > Display > nightlight > OFF

answered Sep 12 '24 at 15:35

surupa123

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