Arch Linux

Szybet

Member

Registered: 2021-11-29

Posts: 9

Backlight works on Garuda, but doesn't on Arch linux

Hello
I have an issue with the backlight, on the lenovo mix 300. Old device based on intel atom CPU. Basically on Arch:

[    2.836542] i915 0000:00:02.0: [drm] *ERROR* Failed to get the SoC PWM chip

and on garuda:

[    5.594391] i915 0000:00:02.0: [drm] Using SoC PWM for LCD backlight control

I have tried many things, obviously updating, different kernels, reinstall, i915 driver options.
Also worth noting, it was working like a year ago on arch too, but just stopped after an update.
More logs:
Not working dmesg: https://gist.github.com/Szybet/fac14194 … adbea0b98b
Working dmesg: https://gist.github.com/Szybet/35412393 … 57907b799d

Any ideas? Thanks

seth

Member

From: Won't reply 2 private help req

Registered: 2012-09-03

Posts: 75,675

Re: Backlight works on Garuda, but doesn't on Arch linux

garuda is some live distro boot?
The chip is accessed ~3s later there.
Also you don't seem to have https://wiki.archlinux.org/title/Microc … ly_loading on arch?
Also compare "lsmod"
Do you have

pacman -Qs firmware

?

---

How to upload text · How to boot w/o GUI · Disable Windows Fast-Start! · Fix your xinitrc

Szybet

Member

Registered: 2021-11-29

Posts: 9

Re: Backlight works on Garuda, but doesn't on Arch linux

You mean this line?:

[    0.013255] ACPI: SSDT 0x000000007CCD4000 0000FF (v01 Insyde SoCDptf  00000003 ACPI 00040000)

Garuda is bloated arch
Yes, i have linux-firmware
I don't see anything interesting in lsmod:
working: https://gist.github.com/Szybet/7936a2fe … 861c0b00fc
not working: https://gist.github.com/Szybet/387f24b2 … 484e9a36b7

also noting: intel_backlight is missing on the not working system

seth

Member

From: Won't reply 2 private help req

Registered: 2012-09-03

Posts: 75,675

Re: Backlight works on Garuda, but doesn't on Arch linux

I know what Garuda is, the question is whther you tested booting an SSD vs. booting a USB key.

Do you have https://wiki.archlinux.org/title/Kernel … _KMS_start ?
(lsinitcpio /boot/intramfs-linux.img | grep i915)

You mean…

…these lines:

[    2.836542] i915 0000:00:02.0: [drm] *ERROR* Failed to get the SoC PWM chip
[    5.594391] i915 0000:00:02.0: [drm] Using SoC PWM for LCD backlight control

Working to not working

< blake2b_generic
> bnep
< btrfs
< cdrom
< dm_log
< dm_mirror
< dm_region_hash
< exfat
> fat
< isofs
> ledtrig_audio
< libcrc32c
< overlay
> nls_iso8859_1
> pcspkr
> pkcs8_key_parser
< qrtr
< raid6_pq
< sg
> snd_ctl_led
< squashfs
< sr_mod
< st
> vfat
< xor
< zram

But there's no acpi or wmi stuff in the diff.

intel_backlight is missing on the not working system

That's the consequence of the i915 error and indicates that the backlight isn't working.

---

How to upload text · How to boot w/o GUI · Disable Windows Fast-Start! · Fix your xinitrc

Szybet

Member

Registered: 2021-11-29

Posts: 9

Re: Backlight works on Garuda, but doesn't on Arch linux

I have firmware, I added microcodes, I have the kms start thing.
I booted garuda from USB, but for example Reborn OS, Arch backlight doesn't work from usb. I also tried putting the bootloader on usb and booting then from it the system on the disk, no success, all acpi_backlight, acpi_osi kernel parameters options also have no effect.
Any ideas?....