Flashing screen upon boot

Ask Fedora
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1

Hello!

I installed Fedora 44 with KDE Plasma. Initially, my brightness was not working, and the only way I could make it work was to run:

sudo grubby --args="acpi_backlight=native" --update-kernel=ALL

Now my brightness adapts, but there is a weird flash upon boot:

  1. after passing GRUB, when the LUKS screen is shown, brightness is on minimum level
  2. after I correctly enter the LUKS password, my laptop’s logo shows up, booting continues, the logo disappears
  3. suddenly the screen goes all white then all black (in a split second, like a flashbomb :D)
  4. the login screen appears with the correct brightness

I tried some throubleshooting, but could not solve it:

  • I disabled the splash screen
  • I tried acpi_backlight=vendor and acpi_backlight=video, these both flashed and the brightness did not work
  • I tried amdgpu.sg_display=0
  • I tried modprobe.blacklist=nouveau rd.driver.blacklist=nouveau
  • I tried booting in both kernels shown at GRUB (6.19.10-300.fc44.x86_64,
    7.2.5-200.fc44.x86_64)

System information:

Operating System: Fedora Linux 44
KDE Plasma Version: 6.7.5
KDE Frameworks Version: 6.30.0
Qt Version: 6.11.2
Kernel Version: 6.19.10-300.fc44.x86_64 (64-bit)
Graphics Platform: Wayland
Processors: 12 × AMD Ryzen 5 4600H with Radeon Graphics
Memory: 8 GiB of RAM (7.1 GiB usable)
Graphics Processor 1: AMD Radeon Graphics
Graphics Processor 2: NVIDIA GeForce GTX 1650
Manufacturer: LENOVO
Product Name: 82B5
System Version: Lenovo Legion 5 15ARH05

My guess is that the nouveau driver is messing with the screen at startup, since I found this log line in systemctl:

nouveau 0000:01:00.0: drm: [DRM/0000000b:kmsOutp] [BL_GET level:0] (ret:-22)

Any hints what I could do? If possible, I would avoid proprietary drivers.
Thanks!

2

It looks to me like you have done no updates since you have the 6.19.10 kernel and fedora is now on the 7.2.5 kernel. Updating may solve all your issues, and you certainly may be chasing an already solved issue with the old software versions you have installed.

You also really should install the nvidia driver from rpmfusion as shown here since that nvidia GPU will perform much better using the nvidia drivers that it will with nouveau.

3

Well, I had the older kernel since as I mentioned, I also tried that one out. I wanted to avoid proprietary drivers, but now I got them, in the hope that they will help.

Now, I am on Kernel Version 7.2.7-200.fc44.x86_64 (64-bit), with akmod-nvidia and xorg-x11-drv-nvidia-cuda installed as mentioned in the howto you linked. Unfortunately, the flash still happens at startup.

4

After searching, i found that the brightness adjustment issue on your hardware / laptop is a bit common. ([SOLVED] Brightness Control Not Working - Lenovo Legion 5 15ARH05 (Ryzen 4800H + GTX 1650)) and the workaround was same, adding the same

acpi_backlight=native

There are several components that can take control of the display during different stages.
what does ls -l /sys/class/backlight/ return?

5 
total 0
lrwxrwxrwx. 1 root root 0 Sep 24 23:19 amdgpu_bl1 -> ../../devices/pci0000:00/0000:00:08.1/0000:05:00.0/drm/card1/card1-eDP-1/amdgpu_bl1
lrwxrwxrwx. 1 root root 0 Sep 24 23:02 nvidia_0 -> ../../devices/pci0000:00/0000:00:01.1/0000:01:00.0/backlight/nvidia_0