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#1 2023-01-19 15:28:35

FaeFeyFa
Member
Registered: 2019-08-08
Posts: 20

[SOLVED] Brightness in kernel 6.1.4 and later

So in kernel 6.1.4 and later on my HP (Envy 15-ds1xxx) laptop, /sys/class/backlight/ is empty.

Searching logs for backlight, I find this:

$ journalctl -b -0 | grep backlight
Jan 17 12:06:34 dream kernel: amdgpu 0000:04:00.0: amdgpu: [drm] Skipping amdgpu DM backlight registration

A bit of Googling reveals that this error was (probably) added in this patch.

Some more information:
A boot with 6.1.3
A boot with 6.1.6

$ lspci -k | grep -A3 VGA
04:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Renoir (rev c2)
	Subsystem: Hewlett-Packard Company Device 87a9
	Kernel driver in use: amdgpu
	Kernel modules: amdgpu

I'm not quite sure what to try from here.

Last edited by FaeFeyFa (2023-01-19 20:54:31)

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#2 2023-01-19 19:07:27

Mortimer Houghton
Member
Registered: 2014-09-28
Posts: 85

Re: [SOLVED] Brightness in kernel 6.1.4 and later

Same thing happened to me on my AMD system.  I resolved it by removing the acpi_backlight=video from the kernel parameters.

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#3 2023-01-19 20:54:19

FaeFeyFa
Member
Registered: 2019-08-08
Posts: 20

Re: [SOLVED] Brightness in kernel 6.1.4 and later

Whoops! I thought I tried that already, but I guess I forgot to run grub-mkconfig...
Thanks!

Last edited by FaeFeyFa (2023-01-19 20:59:51)

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