Automatic Contrast/Gamma Reduction

[insaan (Rohit Sharma)]

Hello, I have been using Fedora for the last 2 months. Since, the last two days the display has suddenly reduced contrast, which makes it difficult to see things.

This problem started around when I downloaded GNOME tweaks to change appearance of leagcy applications to adwaita dark.

Here is my sysinfo:

System Details Report

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Report details

• Date generated: 2024-06-20 08:28:07

Hardware Information:

• Hardware Model: Lenovo IdeaPad 1 15ALC7
• Memory: 8.0 GiB
• Processor: AMD Ryzen™ 5 5500U with Radeon™ Graphics × 12
• Graphics: AMD Radeon™ Graphics
• Disk Capacity: (null)

Software Information:

• Firmware Version: JTCN42WW
• OS Name: Fedora Linux 40 (Workstation Edition)
• OS Build: (null)
• OS Type: 64-bit
• GNOME Version: 46
• Windowing System: Wayland
• Kernel Version: Linux 6.9.4-200.fc40.x86_64

[mblasko (Mike B.)]

Hey Rohit Sharma, welcome to the Fedora community.

The screenshot provided doesn’t show noticeable reduced contrast, except for the fact that Dark Style is active. So it is maybe the screen output distorting the image on your end.

Since you’re making a correlation between the contrast issue and GNOME Tweaks, does resetting the Appearance → Legacy Applications setting remove the issue?

However, this setting should only be affecting legacy gtk applications, so maybe it’s just a coincidence. Are Gtk4 apps affected as well?

[insaan (Rohit Sharma)]

Hello!

I saw the image on my phone and it does seems like that the contrast issue is only happening for the monitor output.

No, reversing it doesn’t corrects the issue. It was just that the contrast issue appeared soon after I applied the setting and restarted my pc. Might be just in my mind.

I have attached 2 images clicked from my phone about the issue. In the second image, I can barely see the RStudio icon.

The contrast problem is affecting the whole display, instead of some specific regions.

[mblasko (Mike B.)]

From the screenshots provided I see two settings (in the Quick Settings menu in the top right corner) that might be the culprit:

• Night Light. This setting reduces the blue component, which in turn makes everything reddish. Easy on the eyes, but not true to the actual colors.
• Screen brightness. I notice it is set to low.

Disabling Night Light, and afterwards increasing brightness if still needed, does correct your issue?

[yuntaz (Y.Z.)]

You can also try switching the power profile from ‘Power Saving’ (which automatically lowers your brightness) to ‘Performance’.

[insaan (Rohit Sharma)]

@yuntaz and @mblasko,

Changing Power Mode to Balanced did solved the issue! It didn’t changed the brightness, but it changed the contrast so I am now able to look at RStudio icon as usual.

However, when I change it back to Power Saver, the problem returns back. It is a problem for me as Balanced mode eats a lot of battery for me (like 1% per minute) while power saver takes only 1% per 8 minutes approximately.

[mblasko (Mike B.)]

With Power Saver on and Night Light off, the issue is still there?

[yuntaz (Y.Z.)]

I encountered this issue with one of my devices this week. In my case, the brightness, contrast or gamma gradually decreased whenever I unplugged the device, and they corrected themselves when the laptop was either connected to AC power or set to performance mode.

I suspect the problem may be related to power-profiles-daemon. I eventually switched to tlp and disabled power-profiles-daemon. You can give it a try using the following commands:

sudo dnf install tlp tlp-rdw -y
sudo systemctl mask power-profiles-daemon.service
sudo systemctl mask systemd-rfkill.service
sudo systemctl mask systemd-rfkill.socket
sudo systemctl enable tlp.service

Additionally, you can undo the above modifications by using systemctl unmask and systemctl disable.

[insaan (Rohit Sharma)]

With Power Saver on and Night Light off, the issue is still there?

Yes.

[mblasko (Mike B.)]

OK. Should you proceed according to @yuntaz 's instructions above, and should it solve your issues, please remember to take notes of the changes performed, in case you would want/need to revert to the initial setup sometime in the future.

[insaan (Rohit Sharma)]

Hey, it worked. Though i just reverted it later and shifted to balanced mode since it was now working nicely.

[manual (Aniket Mujumdar)]

Hey, I am having the same issue but I’m on silverblue-nvidia 40, for me only performance mode seems to not change the contrast, both power save mode and balanced mode seem to change the contrast when unplugged, it’s just the effect is much more pronounced in power saver mode.

I would like to avoid layering TLP and I don’t feel like this is a solution, so any other way to fix this?

Linking some pictures to make it more clear what is happening.

Power saver mode
Unplugged =>

Plugged in =>

Sorry for the terrible pics couldn’t find an image editor

[yuntaz (Y.Z.)]

Yes, you can disable panel power saving without removing power-profile-daemon. But this setting only affects integrated Radeon graphics, not Nvidia.

From

upower / power-profiles-daemon · GitLab

If you decide that you don’t like how this behaves, you can disable the function in one of two ways:

1. Adding amdgpu.abmlevel=0 to the kernel command line. This will disable abm value changes entirely.
2. By using --block-action=amdgpu_panel_power in the power-profiles-daemon ExecStart command. This will allow you to still change values manually in sysfs but power-profiles-daemon will not change anything.

I personally use the first solution:

rpm-ostree kargs --append-if-missing 'amdgpu.abmlevel=0'

[manual (Aniket Mujumdar)]

A bit more information on this, I have an external monitor that’s not connected directly to my dGPU (nvidia, i.e. no MUX switch) and when I enable the power saving mode, only the laptop monitor has this issue. The external monitor seems to be unaffected.

Also linking the discussion of this issue on the PPD side for reference : PPD Issue

TLDR : Currently Power saving mode will reduce the contrast and currently there is no way to use power saving without reducing contrast, is my take away.

[yuntaz (Y.Z.)]

You can also give TLP a try. I think panel power saving shouldn’t affect NVIDIA laptop. And if TLP does resolve this issue, maybe report it to upower.