Brightness control does not work for laptop display on Dell Alienware m15 R5
Brief summary of the problem:
Brightness control does not work for laptop display on Dell Alienware m15 R5. The brightness seems to be staying at maximum.
Hardware description:
- CPU: AMD 5800H
- GPU: AMD 5800H and Nvidia RTX 3060
- System Memory: 16GB
- Display(s): laptop internal display
- Type of Diplay Connection: eDP
System information:
- Distro name and Version: Fedora 34
- Kernel version: 5.13.6-200.fc34.x86_64
- Custom kernel: N/A
- AMD package version: xorg-x11-drv-amdgpu-19.1.0-8.fc34.x86_64
How to reproduce the issue:
- Enable hybrid graphics/Optimus in BIOS setup, so that the display will be connected to the AMD GPU.
- Try to change brightness from GNOME or write into
/sys/class/backlight/amdgpu_bl1/brightness
. The display brightness doesn't change. - Looking inside
/sys/class/backlight/
, there is only one directoryamdgpu_bl1
.max_brightness
is 255.actual_brightness
follows the value written intobrightness
. - The
amdgpu.backlight=0
kernel parameter mentioned in #1438 (closed) doesn't help here. -
acpi_backlight=vendor
oracpi_backlight=native
oracpi_backlight=none
makes no difference. Withacpi_backlight=video
there is anotheracpi_video0
in addition toamdgpu_bl1
in/sys/class/backlight/
but neither of them has any effect. - If hybrid graphics is disabled, the display is connected to the Nvidia GPU, the Nvidia proprietary driver can change the display brightness without problem. In this case there is only
nvidia_0
in/sys/class/backlight/
withmax_brightness
100. - In Windows 10 OS and hybrid graphics mode, the brightness control works if the AMD driver (21.6.1 downloaded from AMD website) is installed and enabled and it doesn't work if the AMD driver is not installed or disabled, regardless of the status of Nvidia driver too.
Attached files:
- Dmesg log dmesg.log
- Xorg log Xorg.0.log Xorg.1.log