Re: Backlight control does not work no entries /sys/class/backlight

On Sat, 2025-09-27 at 09:03 +0000, Cliff mcDiarmid wrote:
> This I believe is governed by the driver 'amdgpu' which is showing as a loaded
> module.   There are errors though from the journald:
> 
> [    1.656378] amdgpu: ATOM BIOS: 113-RENOIR-026
> [    1.658532] amdgpu 0000:04:00.0: Direct firmware load for amdgpu/
> renoir_asd.bin failed with error -2
> [    1.660242] [drm:amdgpu_device_init.cold [amdgpu]] *ERROR* early_init of IP
> block <psp> failed -19
> [    1.662661] amdgpu 0000:04:00.0: Direct firmware load for amdgpu/
> renoir_dmcub.bin failed with error -2
> [    1.664232] [drm:amdgpu_device_init.cold [amdgpu]] *ERROR* early_init of IP
> block <dm> failed -19
> [    1.665266] amdgpu 0000:04:00.0: Direct firmware load for amdgpu/
> renoir_pfp.bin failed with error -2
> [    1.665274] [drm:amdgpu_device_init.cold [amdgpu]] *ERROR* early_init of IP
> block <gfx_v9_0> failed -19
> [    1.666143] amdgpu 0000:04:00.0: Direct firmware load for amdgpu/
> renoir_sdma.bin failed with error -2
> [    1.666154] [drm:amdgpu_device_init.cold [amdgpu]] *ERROR* early_init of IP
> block <sdma_v4_0> failed -19
> [    1.675952] amdgpu 0000:04:00.0: Direct firmware load for amdgpu/
> renoir_vcn.bin failed with error -2
> [    1.677838] [drm:amdgpu_device_init.cold [amdgpu]] *ERROR* early_init of IP
> block <vcn_v2_0> failed -19
> [    1.680059] amdgpu 0000:04:00.0: amdgpu: Fatal error during GPU init
> [    1.681625] amdgpu 0000:04:00.0: amdgpu: amdgpu: finishing device.
> 
> The module is loading but I'm assuming these errors impact the backlight
> setup?

It's not only impacting the backlight setup, but almost all the
functions of the GPU.  You are likely running the system on the VESA or
EFI framebuffer using LLVMpipe as the GL driver, thus most functions of
the GPU do not work.

> So I loaded the latest linux firmware for AMD followed by the firmware from
> Tuxedo - neither has made any difference.

What do you mean by no difference?  If the error message lines are still
there when you reboot it means something is still wrong.

One possible reason is the AMDGPU driver was built as a part of vmlinux
instead of a module.  As the book already said (in the Mesa page), don't
do that:

   Selecting CONFIG_DRM_RADEON, CONFIG_DRM_AMDGPU, or CONFIG_DRM_NOUVEAU
   as “y” is not recommended. If it is, any required firmware must be
   built as a part of the kernel image or the initramfs for the driver
   to function correctly.

If this is your case, rebuild the kernel with CONFIG_DRM_AMDGPU=m
instead of y.

Another possible reason is you simply installed the firmware files into
a wrong location.

-- 
Xi Ruoyao <[email protected]>

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