Backlight brightness very low when using nvidia-driver-510 or newer. (Ubuntu 22.04)

I just tried driver 530 as well, and I can confirm, max brightness is still very low.
…rolling back to version 470. :(

According NVidia driver 530 documentation at this link: Chapter 16. Configuring a Notebook
There is (or was) an option to disable the backlight handler, by passing the

NVreg_EnableBacklightHandler=0

parameter to the nvidia kernel module.
This would most likely solve the dim backlight problem, but unfortunately, it seems this option was removed after driver 470, even though it is still mentioned in the documentation.
Running “modinfo nvidia” shows that it is gone.
Is this a temporary bug, or was this feature removed permanently. If so, why is it still in the docs?
Also, what is the point of paying a premium for a laptop with certified NVidia GSync display, if the display is not compatible with the latest NVidia drivers?

Unfortunately, the latest CUDA Toolkit requires updated drivers, so I can’t install CUDA without borking my display. As a workaround, I bought an AMD Radeon eGPU, so I can port my CUDA code to ROCm.

1 Like

ben.emoji.isThisThingOn_alphaBG

Hi - it’s been 6 months …

Note the previous discussion on this was closed (unsolved):

Unfortunately there was confusion between the BACKLIGHT and the ability to adjust the brightness. Oh dear. The problem is not adjustable brightness. The BACKLIGHT is turned off when the nvidia driver updates > v470 (!)

I have just tried 535.113.01 still bad. The laptop display goes very dim. hard to read. The 2nd monitor (attached by HDMI) is fine.

GOOD LAPTOP BACKLIGHT: 470.199.02
BAD LAPTOP BACKLIGHT: 535.113.01

Please notice this driver has been broken for YEARS. Does NVidia still do computer graphics?

This 17" razer blade pro has a 4K IGZO Touch Display UHD 3840x2160 with NVidia GSync
Still a very good display…

It’s becoming an issue having to revert to version 470.

output from “kscreen-console bug” is attached.
kscreen.console.txt (16.2 KB)

lshw -C display

*-display
description: VGA compatible controller
product: GP104BM [GeForce GTX 1080 Mobile]
vendor: NVIDIA Corporation
physical id: 0
bus info: pci@0000:01:00.0
version: a1
width: 64 bits
clock: 33MHz
capabilities: pm msi pciexpress vga_controller bus_master cap_list rom
configuration: driver=nvidia latency=0
resources: irq:150 memory:db000000-dbffffff memory:b0000000-bfffffff memory:c0000000-c1ffffff ioport:e000(size=128) memory:c0000-dffff
*-graphics
product: EFI VGA
physical id: 3
logical name: /dev/fb0
capabilities: fb
configuration: depth=32 resolution=800,600

During the Gentoo install of x11-drivers/nvidia-drivers-525.125.06
The word backlight appears twice:

CONFTEST: acpi_video_backlight_use_native

CONFTEST: get_backlight_device_by_name

@2024a - pls respond/help? – can you slice the diff for what happens to the backlight after v470?

Stuck at nvidia-driver version 470.199.02

01:00.0 VGA compatible controller: NVIDIA Corporation GP104BM [GeForce GTX 1080 Mobile] (rev a1) (prog-if 00 [VGA controller])

I had couple of razer blade notebooks handy with Ada and ampere graphics card where I cannot see backlight brightens issue.
I am trying to find similar notebook model with pascal architecture for local reproduction.
Meanwhile, could you please try below command manually and share backlight brightness behavior?
echo n > /sys/class/backlight/nvidia_0/brightness
where n is an integer from 0 to 100 in the increment of 10.
You can also try decreasing its value as well from 100 to 0 in decrement of 10 to confirm its behavior.

Hi All,
Could you please try below command manually and share backlight brightness behavior?
echo n > /sys/class/backlight/nvidia_0/brightness
where n is an integer from 0 to 100 in the increment of 10.
You can also try decreasing its value as well from 100 to 0 in decrement of 10 to confirm its behavior.

Hi,
Thanks for the response!! Yes, the backlight entry is there, but it does nothing when it is changed.

razer ~ $ echo 50 >  /sys/class/backlight/nvidia_0/brightness
bash: /sys/class/backlight/nvidia_0/brightness: Permission denied

razer ~ $ su
Password: 
razer /home/ben # echo 50 >  /sys/class/backlight/nvidia_0/brightness
razer /home/ben # echo 0 >  /sys/class/backlight/nvidia_0/brightness
razer /home/ben # echo 100 >  /sys/class/backlight/nvidia_0/brightness
razer /home/ben # 
razer /home/ben # cat /sys/class/backlight/nvidia_0/brightness
100
razer ~ # echo 89 > /sys/class/backlight/nvidia_0/brightness
razer ~ # cat /sys/class/backlight/nvidia_0/brightness
89
razer ~ # echo 100 >  /sys/class/backlight/nvidia_0/brightness

xrandr does work - it makes the display dimmer. However, the problem is the display is already too dim (because the backlight is OFF).

The Subject Line should be: Backlight OFF - not Backlight “very low”.

razer /home/ben # /usr/bin/xrandr
Screen 0: minimum 8 x 8, current 7680 x 2160, maximum 32767 x 32767
HDMI-0 connected 3840x2160+0+0 (normal left inverted right x axis y axis) 597mm x 336mm
   3840x2160     60.00*+  59.94    29.97    25.00    23.98  
   2560x1440     59.95  
   2048x1280     60.00  
   1920x1080     60.00    59.94    50.00    25.00    23.98    60.00    50.04  
   1600x1200     60.00  
   1600x900      60.00  
   1280x1024     75.02    60.02  
   1280x720      59.94  
   1152x864      75.00  
   1024x768      75.03    60.00  
   800x600       75.00    60.32  
   720x576       50.00  
   720x480       59.94  
   640x480       75.00    59.94    59.93  
DP-0 connected primary 3840x2160+3840+0 (normal left inverted right x axis y axis) 382mm x 215mm
   3840x2160     60.00*+  30.00  
DP-1 disconnected (normal left inverted right x axis y axis)
DP-2 disconnected (normal left inverted right x axis y axis)

razer /home/ben # /usr/bin/xrandr --output DP-0 --brightness 0.5
razer /home/ben # /usr/bin/xrandr --output DP-0 --brightness 0.1
razer /home/ben # /usr/bin/xrandr --output DP-0 --brightness 1.0
razer /home/ben #

The nvidia GPU is fully exposed, as usual, in /sys/devices (and indeed /sys/class)

razer /home/ben # ls -la /sys/class/backlight/nvidia_0/
total 0
drwxr-xr-x 3 root root    0 Nov 21 09:06 .
drwxr-xr-x 3 root root    0 Nov 21 09:06 ..
-r--r--r-- 1 root root 4096 Nov 21 10:06 actual_brightness
-rw-r--r-- 1 root root 4096 Nov 21 10:06 bl_power
-rw-r--r-- 1 root root 4096 Nov 21 10:13 brightness
lrwxrwxrwx 1 root root    0 Nov 21 10:06 device -> ../../../0000:01:00.0
-r--r--r-- 1 root root 4096 Nov 21 10:02 max_brightness
drwxr-xr-x 2 root root    0 Nov 21 10:06 power
-r--r--r-- 1 root root 4096 Nov 21 10:06 scale
lrwxrwxrwx 1 root root    0 Nov 21 09:10 subsystem -> ../../../../../../class/backlight
-r--r--r-- 1 root root 4096 Nov 21 10:06 type
-rw-r--r-- 1 root root 4096 Nov 21 09:10 uevent

razer /home/ben # ls -la /sys/class/backlight/nvidia_0/power/
total 0
drwxr-xr-x 2 root root    0 Nov 21 10:06 .
drwxr-xr-x 3 root root    0 Nov 21 09:06 ..
-rw-r--r-- 1 root root 4096 Nov 21 10:14 autosuspend_delay_ms
-rw-r--r-- 1 root root 4096 Nov 21 10:14 control
-r--r--r-- 1 root root 4096 Nov 21 10:14 runtime_active_time
-r--r--r-- 1 root root 4096 Nov 21 10:14 runtime_status
-r--r--r-- 1 root root 4096 Nov 21 10:14 runtime_suspended_time

razer /home/ben # cat /sys/class/backlight/nvidia_0/power/control
auto

razer /home/ben # more /sys/class/backlight/nvidia_0/power/*
::::::::::::::
/sys/class/backlight/nvidia_0/power/autosuspend_delay_ms
::::::::::::::
::::::::::::::
/sys/class/backlight/nvidia_0/power/control
::::::::::::::
auto
::::::::::::::
/sys/class/backlight/nvidia_0/power/runtime_active_time
::::::::::::::
0
::::::::::::::
/sys/class/backlight/nvidia_0/power/runtime_status
::::::::::::::
unsupported
::::::::::::::
/sys/class/backlight/nvidia_0/power/runtime_suspended_time
::::::::::::::
0


razer /home/ben # equery l nvidia-drivers
 * Searching for nvidia-drivers ...
[IP-] [  ] x11-drivers/nvidia-drivers-470.199.02:0/470

I will have to send the same test for a version > 470 (where the backlight is off)
apologies - this razer is currently running the old v470 because this is where
the backlight is still on (and i can read the screen!)

The razer has had Linux NVidia Driver 545.29.02 installed, and has booted into it.
The laptop display is dark again. This is the problem.
There is also a 2nd monitor attached by HDMI cable. it is fine; same as before.

Here are the same commands, now with the new driver - note the backlight is now OFF

razer /mnt/home/ben $ su
Password: 

razer /mnt/home/ben # uname -a
Linux where.nowhere 5.15.88-gentoo-x86_64 #6 SMP Wed Oct 11 08:51:33 AEDT 2023 x86_64 Intel(R) Core(TM) i7-6700HQ CPU @ 2.60GHz GenuineIntel GNU/Linux

razer /mnt/home/ben # equery l nvidia-drivers
 * Searching for nvidia-drivers ...
[IP-] [  ] x11-drivers/nvidia-drivers-545.29.02:0/545
 
razer /mnt/home/ben # date
Wed Nov 22 10:45:03 AEDT 2023

razer /mnt/home/ben # cat /sys/class/backlight/nvidia_0/brightness
100

razer /mnt/home/ben # echo 50 >  /sys/class/backlight/nvidia_0/brightness
bash: echo: write error: Invalid argument

razer /mnt/home/ben # ls -la /sys/class/backlight/nvidia_0/brightness
-rw-r--r-- 1 root root 4096 Nov 22 10:45 /sys/class/backlight/nvidia_0/brightness

razer /mnt/home/ben # cat /sys/class/backlight/nvidia_0/actual_brightness 
100

razer /mnt/home/ben # echo 50 >  /sys/class/backlight/nvidia_0/actual_brightness
bash: /sys/class/backlight/nvidia_0/actual_brightness: Permission denied

razer /mnt/home/ben # ls -la /sys/class/backlight/nvidia_0/          
total 0
drwxr-xr-x 3 root root    0 Nov 22 09:23 .
drwxr-xr-x 3 root root    0 Nov 22 09:23 ..
-r--r--r-- 1 root root 4096 Nov 22 10:45 actual_brightness
-rw-r--r-- 1 root root 4096 Nov 22 10:45 bl_power
-rw-r--r-- 1 root root 4096 Nov 22 10:45 brightness
lrwxrwxrwx 1 root root    0 Nov 22 09:30 device -> ../../../0000:01:00.0
-r--r--r-- 1 root root 4096 Nov 22 09:30 max_brightness
drwxr-xr-x 2 root root    0 Nov 22 10:45 power
-r--r--r-- 1 root root 4096 Nov 22 10:45 scale
lrwxrwxrwx 1 root root    0 Nov 22 09:31 subsystem -> ../../../../../../class/backlight
-r--r--r-- 1 root root 4096 Nov 22 09:30 type
-rw-r--r-- 1 root root 4096 Nov 22 09:31 uevent

razer /mnt/home/ben # more /sys/class/backlight/nvidia_0/*
::::::::::::::
/sys/class/backlight/nvidia_0/actual_brightness
::::::::::::::
100
::::::::::::::
/sys/class/backlight/nvidia_0/bl_power
::::::::::::::
0
::::::::::::::
/sys/class/backlight/nvidia_0/brightness
::::::::::::::
50

*** /sys/class/backlight/nvidia_0/device: directory ***

::::::::::::::
/sys/class/backlight/nvidia_0/max_brightness
::::::::::::::
100

*** /sys/class/backlight/nvidia_0/power: directory ***

::::::::::::::
/sys/class/backlight/nvidia_0/scale
::::::::::::::
unknown

*** /sys/class/backlight/nvidia_0/subsystem: directory ***

::::::::::::::
/sys/class/backlight/nvidia_0/type
::::::::::::::
raw
::::::::::::::
/sys/class/backlight/nvidia_0/uevent
::::::::::::::
razer /mnt/home/ben #

Pls note the command fails this time!

echo 50 >  /sys/class/backlight/nvidia_0/brightness
bash: echo: write error: Invalid argument

The laptop screen is too dark to use. I have to revert it, to v470.
btw, the xrandr commands do work, and makes the screen darker.

The problem is the Backlight is clearly OFF. It needs to be ON.
This 4K screen has IGZO & NVidia G-Sync.

any assistance appreciated.

regards,
ben.

Hello! happy 3D day - 3rd of December 2023.

this topic is still open, since 26-Oct-2022. Unsolved.

Perhaps it could be fixed in the open-source version of the driver?
Is that a reality? Is the open-source version up to the same version of the private binary/firmware?

b.

@fortythree
Sory for taking longer time to repro issue locally.
Could you please do us a favor one more time by sharing nvidia bug report from repro driver.

@fortythree
Could you please do us a favor one more time by sharing nvidia bug report from repro driver.

@fortythree
Could you please do us a favor one more time by sharing nvidia bug report from repro driver.

Hi All,
I would request to please confirm if anyone is still seeing brightness issue with latest release driver.
If yes, please share laptop model along with nvidia bug report.