Screen Brightness Not working on iMac with Radeon HD 4670
Hello.
I've installed Fedora 35 on my late 2009 21.5" iMac with AMD Mobility Radeon HD 4670 as its graphics card.
uname -r: 5.16.18-200.fc35.x86_64
However, if I ls /sys/class/backlight
, I only get acpi_video0
which if I'm not mistaken, it's the integrated Intel chip.
As a side note, the installation was giving me a blank screen which I solved with radeon.modeset=0 nomodeset
for the time being during the installation.
Anyways, now the system works fine except that I can't change my screen brightness.
lspci -v:
01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] RV730/M96-XT [Mobility Radeon HD 4670] (prog-if 00 [VGA controller])
Subsystem: Apple Inc. Device 00b6
Flags: bus master, fast devsel, latency 0
Memory at c0000000 (64-bit, prefetchable) [size=256M]
Memory at d0420000 (64-bit, non-prefetchable) [size=64K]
I/O ports at 2000 [size=256]
Expansion ROM at d0400000 [disabled] [size=128K]
Capabilities: <access denied>
Kernel modules: radeon, amdgpu
As you can see, the system loads the Radeon
driver first which I tried to disable but I couldn't succeed.
Here is some more debugging information.
xrandr:
xrandr: Failed to get size of gamma for output default
Screen 0: minimum 1920 x 1080, current 1920 x 1080, maximum 1920 x 1080
default connected primary 1920x1080+0+0 0mm x 0mm
1920x1080 77.00*
dmesg | grep amd:
[ 0.000000] Command line: BOOT_IMAGE=(hd3,gpt2)/vmlinuz-5.16.18-200.fc35.x86_64 root=UUID=aba08c60-026a-4f27-9434-0e226f5a91b9 ro rootflags=subvol=root nomodeset rhgb quiet radeon.si_support=0 amdgpu.si_support=1
[ 0.122709] Kernel command line: BOOT_IMAGE=(hd3,gpt2)/vmlinuz-5.16.18-200.fc35.x86_64 root=UUID=aba08c60-026a-4f27-9434-0e226f5a91b9 ro rootflags=subvol=root nomodeset rhgb quiet radeon.si_support=0 amdgpu.si_support=1
[ 10.092120] [drm:amdgpu_init [amdgpu]] *ERROR* VGACON disables amdgpu kernel modesetting.
[ 13.653697] [drm:amdgpu_init [amdgpu]] *ERROR* VGACON disables amdgpu kernel modesetting.
dmesg | grep radeon:
[ 0.000000] Command line: BOOT_IMAGE=(hd3,gpt2)/vmlinuz-5.16.18-200.fc35.x86_64 root=UUID=aba08c60-026a-4f27-9434-0e226f5a91b9 ro rootflags=subvol=root nomodeset rhgb quiet radeon.si_support=0 amdgpu.si_support=1
[ 0.122709] Kernel command line: BOOT_IMAGE=(hd3,gpt2)/vmlinuz-5.16.18-200.fc35.x86_64 root=UUID=aba08c60-026a-4f27-9434-0e226f5a91b9 ro rootflags=subvol=root nomodeset rhgb quiet radeon.si_support=0 amdgpu.si_support=1
[ 9.598034] [drm] VGACON disable radeon kernel modesetting.
[ 9.598039] [drm:radeon_module_init [radeon]] *ERROR* No UMS support in radeon module!
Is there an issue with the driver somewhere that my card isn't supported or is this just a configuration issue on my end?
Thanks.