Unable to adjust screen backlight brightness on Google Pixelbook Eve

[Andrius]

The machine is Pixelbook 2017 Eve. OS is 21.10 fresh install and there is no way to adjust the screen backlight brightness. It is 100% all the time. IN 21.04 the solution was to add to kernel command line the i915.enable_dpcd_backlight=1 however this does not work in 21.10.

ProblemType: Bug
DistroRelease: Ubuntu 21.10
Package: xorg 1:7.7+22ubuntu2
ProcVersionSignature: Ubuntu 5.13.0-20.20-generic 5.13.14
Uname: Linux 5.13.0-20-generic x86_64
ApportVersion: 2.20.11-0ubuntu71
Architecture: amd64
BootLog: Error: [Errno 13] Permission denied: '/var/log/boot.log'
CasperMD5CheckResult: pass
CompositorRunning: None
CurrentDesktop: ubuntu:GNOME
Date: Sat Nov 6 22:38:37 2021
DistUpgraded: Fresh install
DistroCodename: impish
DistroVariant: ubuntu
ExtraDebuggingInterest: Yes, if not too technical
GraphicsCard:
 Intel Corporation HD Graphics 615 [8086:591e] (rev 02) (prog-if 00 [VGA controller])
   Subsystem: Google, Inc. HD Graphics 615 [1ae0:2212]
InstallationDate: Installed on 2021-11-06 (0 days ago)
InstallationMedia: Ubuntu 21.10 "Impish Indri" - Release amd64 (20211012)
Lsusb:
 Bus 002 Device 003: ID 0951:1666 Kingston Technology DataTraveler 100 G3/G4/SE9 G2/50
 Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
 Bus 001 Device 003: ID 8087:0a2a Intel Corp. Bluetooth wireless interface
 Bus 001 Device 002: ID 0bda:564b Realtek Semiconductor Corp. WebCamera
 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
MachineType: Google Eve
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=lt_LT.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-5.13.0-20-generic root=/dev/mapper/vgubuntu-root ro i915.enable_dpcd_backlight=0 quiet splash vt.handoff=7
SourcePackage: xorg
Symptom: display
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 08/06/2021
dmi.bios.release: 4.14
dmi.bios.vendor: coreboot
dmi.bios.version: MrChromebox-4.14
dmi.board.name: Eve
dmi.board.vendor: Google
dmi.board.version: 1.0
dmi.chassis.type: 31
dmi.chassis.vendor: Google
dmi.ec.firmware.release: 0.0
dmi.modalias: dmi:bvncoreboot:bvrMrChromebox-4.14:bd08/06/2021:br4.14:efr0.0:svnGoogle:pnEve:pvr1.0:sku:rvnGoogle:rnEve:rvr1.0:cvnGoogle:ct31:cvr:
dmi.product.family: Google_Eve
dmi.product.name: Eve
dmi.product.version: 1.0
dmi.sys.vendor: Google
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.107-8ubuntu1
version.libgl1-mesa-dri: libgl1-mesa-dri 21.2.2-1ubuntu1
version.libgl1-mesa-glx: libgl1-mesa-glx N/A
version.xserver-xorg-core: xserver-xorg-core 2:1.20.13-1ubuntu1
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:19.1.0-2build1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20200714-1ubuntu2
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.17-1build1

[Andrius (kaikaris-andrius)]

Tried also i915.enable_dpcd_backlight=0
Thats what the latest log shows

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This change was made by a bot.

[Tobias Karnat (tobiaskarnat)]

I have the same issue with my Lenovo Ideapad Duet 3i - Bug 1951692
https://bugs.launchpad.net/ubuntu/+source/linux-hwe-5.13/+bug/1951692

There are patches available upstream to fix this issue.
https://patchwork.freedesktop.org/series/95127/

Freedesktop bug report
https://gitlab.freedesktop.org/drm/intel/-/issues/3680