AMD Ryzen 5 4600H Renoir iGPU backlight brightness control not working (Hybrid Graphics) (Lenovo Legion 5 15ARH05)

Brief summary of the problem:

Hi, after resolving #1438 (closed) I tested if my laptop's screen backlight works out of the box without any action. It's not until I add amdgpu.backlight=0 as the kernel parameter.

Hardware description:

• CPU: AMD Ryzen 5 4600H
• GPU: Nvidia Geforce GTX 1650
• System Memory: 16GB DDR4@3200MHz
• Display(s): Laptop Screen
• Type of Display Connection: eDP

System information:

• Distro name and Version: OpenSuse Tumbleweed, ArchLinux November Live ISO
• Kernel version: 5.14.14-2-default, 5.14.15.arch1-1
• AMD official driver version: Not sure how to check

How to reproduce the issue:

1. Enable Switchable Graphics from BIOS.
2. Boot the Live ISO.
3. Try to write values to /sys/class/backlight/amdgpu_bl1/brightness.
4. Value is changed but screen stays at maximum brightness.
5. Boot the ISO with amdgpu.backlight=0 parameter and try step 2. Observe that brightness changes.

Logs

dmesg

Please attach your dmesg output. Do you have multiple backlights under /sys/class/backlight/? If so, do any of the others work? If this is a regression can you bisect? https://www.kernel.org/doc/html/latest/admin-guide/bug-bisect.html

There's only 1 entry. I've attached dmesg to the original post. I think it didn't work before without kernel parameter.

EDIT: I also talked with @antonyjr who reported #1438 (closed) and it works on his hardware without problems.

changed the description

marked #1794 (closed) as a duplicate of this issue

marked this issue as related to #1794 (closed)

@agd5f I created the issue #1794 (closed) that you closed. On my device, the brightness isn't working even with amdgpu.backlight=0 kernel parameter even on the newest kernel 5.15. I have mentioned all the details of my device in the issue. My device also has MUX switch if that can cause issues.

Does this patch fix it?

https://patchwork.freedesktop.org/patch/463485/

Just updated Tumbleweed to 5.15.2-1-default and it works out of the box. I'll close issue for now.

closed

@agd5f on the newest 5.16.1-arch1-1 kernel it doesn't work again. It broke somewhere between 5.15.2 and 5.15.10. It works on December arch ISO but not January. I've also tried openSUSE-Tumbleweed-KDE-Live-x86_64-Snapshot20220114-Media.iso. If I add previously mentioned kernel parameter it works.

dmesg.log

journal.log

can you bisect between those kernels perhaps?

reopened

This might be a duplicate of #1671 (closed) . Can you try the suggestions there? Enable NVIDIA_WMI_EC_BACKLIGHT in your config.

I've tried to sudo modprobe nvidia-wmi-ec-backlight that since it's compiled as module on default Arch kernel but no new entry appears.

❯ ls -la /sys/class/backlight/
razem 0
drwxr-xr-x  2 root root 0 03-25 11:11 .
drwxr-xr-x 77 root root 0 03-25 11:11 ..
lrwxrwxrwx  1 root root 0 03-25 11:12 amdgpu_bl0 -> ../../devices/pci0000:00/0000:00:08.1/0000:05:00.0/backlight/amdgpu_bl0
lrwxrwxrwx  1 root root 0 03-25 11:12 nvidia_0 -> ../../devices/pci0000:00/0000:00:01.1/0000:01:00.0/backlight/nvidia_0

mentioned in issue #1671 (closed)

mentioned in issue #2052 (closed)

@agd5f if I'm not mistaken that set of patches should solve the issue for real this time? https://www.phoronix.com/news/2022-Linux-Backlight-Overhaul

Maybe, worth a try.

NVIDIA_WMI_EC_BACKLIGHT should control the backlight on these systems.

closed