Brightness control not working on Fedora 39

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1

Hi,

I have been using Fedora for the last 4-5 releases, and had no issues.
Also this is the first time in over 10 years that I couldn’t DuckDuckGo my way to a solution. That being said, when I upgraded to Fedora 39 from 38, my GPU setting in /sys/class/backlight disappeared with the new kernel vmlinuz-6.5.11-300.fc39.x86_64

What linux kernel parameter can I use for amdgpu screen brightness. I’ve tried
these with the amdgpu-install-5.5.50503-1.el9.noarch.rpm driver from the AMD
website.

I have tried adding these options, one at a time to /etc/default/grub

backlight=amdgpu_bl1
acpi_backlight=native
acpi_backlight=vendor
acpi_backlight=linux
amdgpu.backlight=0
amdgpu.dc_backlight=1
acpi_osi=linux

This is my GPU info

acpi_backlight=vendor

           *-display
                description: VGA compatible controller
                product: Picasso/Raven 2 [Radeon Vega Series / Radeon Vega Mobile Series]
                vendor: Advanced Micro Devices, Inc. [AMD/ATI]
                physical id: 0
                bus info: pci@0000:05:00.0
                logical name: /dev/fb0
                version: c4
                width: 64 bits
                clock: 33MHz
                capabilities: pm pciexpress msi msix vga_controller bus_master cap_list fb
                configuration: depth=32 driver=amdgpu latency=0 resolution=1920,1080
                resources: irq:63 memory:b0000000-bfffffff memory:c0000000-c01fffff ioport:10
2

Still looking but have more details.

amd-default-driver_vf38.log

  lspci -n -n -k | grep -A 2 -e VGA -e 3D
  
  05:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Picasso/Ra  ven 2 [Radeon Vega Series / Radeon Vega Mobile Series] [1002:15d8] (rev c4)
      Subsystem: Acer Incorporated [ALI] Device [1025:134f]
      Kernel driver in use: amdgpu
  
  switcherooctl list
  
  Device: 0
    Name:        Advanced Micro Devices, Inc. [AMD®/ATI] Picasso/Raven 2 [Radeon Vega Series   / Radeon Vega Mobile Series]
    Default:     yes
    Environment: DRI_PRIME=pci-0000_05_00_0
  
  /sys/class/backlight/
  amdgpu_bl1

amd-default-driver_vf39.log

  lspci -n -n -k | grep -A 2 -e VGA -e 3D
  
  05:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Picasso/Ra  ven 2 [Radeon Vega Series / Radeon Vega Mobile Series] [1002:15d8] (rev c4)
      Subsystem: Acer Incorporated [ALI] Device [1025:134f]
      Kernel modules: amdgpu
  
  switcherooctl list
  *blank*
  
  /sys/class/backlight/
  *blank*
3

Using the proprietary amdgpu-pro driver is not recommended, it’s very problematic. Fedora includes opensource AMD drivers which work out of the box with better stability and performance.

Burn a Fedora 39 Worktation Live image to a USB and boot from it. Does the brightness control work from the Live system? If it does, then the problem is most likely in the amdgpu-pro driver that you installed. Uninstall it and go back to the Fedora-provided opensource drivers.

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