This change was made by a bot.
** Changed in: linux (Ubuntu)
Status: New => Confirmed
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https://bugs.launchpad.net/bugs/1895615
Title:
Backlight adjustment doesn't work on Google Pixel Slate
Status in linux package in Ubuntu:
Confirmed
Bug description:
The Pixel Slate/nocturne backlight does not work due to DPCD logic not
identifying the DPCD backlight connection since there is no PWM on the
nocturne or eve devices.
ChromeOS documentation of disconnected PWM: https://chromium-
review.googlesource.com/c/chromiumos/overlays/board-overlays/+/1171922
Discussion of issue & solution: https://github.com/EmbeddedAndroid
/linux-eve/issues/2#issuecomment-561382927
This can be fixed with a simple patch which I have applied successfully to
mainline 5.9-rc5:
https://gist.github.com/satmandu/d6c2192f66cd14525049fd34d356d71d
Luckily the Ubuntu kernel patches set i915.enable_psr=0 which keeps
Panel Self Refresh from dimming the backlight at boot, but that isn't
even needed for this device once the backlight is hooked up correctly.
(As a bonus the keyboard backlight also starts working properly at
boot.)
ProblemType: Bug
DistroRelease: Ubuntu 20.10
Package: linux-image-lowlatency 5.8.0.18.22
ProcVersionSignature: Ubuntu 5.8.0-18.19-lowlatency 5.8.4
Uname: Linux 5.8.0-18-lowlatency x86_64
ApportVersion: 2.20.11-0ubuntu45
Architecture: amd64
AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq',
'/dev/snd/timer'] failed with exit code 1:
CasperMD5CheckResult: skip
Date: Mon Sep 14 23:52:45 2020
InstallationDate: Installed on 2020-08-24 (21 days ago)
InstallationMedia: Ubuntu 20.10 "Groovy Gorilla" - Alpha amd64 (20200728)
Lsusb:
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 003: ID 18d1:5030 Google Inc. Hammer
Bus 001 Device 002: ID 8087:0a2a Intel Corp. Bluetooth wireless interface
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
MachineType: Google Nocturne
ProcEnviron:
TERM=xterm-256color
PATH=(custom, no user)
LANG=en_US.UTF-8
SHELL=/bin/bash
ProcFB: 0 i915drmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.8.0-18-lowlatency
root=UUID=90e26b2a-aaad-4576-8e90-1962b97d4e96 ro fsck.repair=yes
fsck.mode=force
PulseList:
Error: command ['pacmd', 'list'] failed with exit code 1: Home directory not
accessible: Permission denied
No PulseAudio daemon running, or not running as session daemon.
RelatedPackageVersions:
linux-restricted-modules-5.8.0-18-lowlatency N/A
linux-backports-modules-5.8.0-18-lowlatency N/A
linux-firmware 1.190
SourcePackage: linux
StagingDrivers: ipu3_imgu
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 06/04/2019
dmi.bios.release: 4.0
dmi.bios.vendor: coreboot
dmi.bios.version: Google_Nocturne.10984.90.0
dmi.board.name: Nocturne
dmi.board.vendor: Google
dmi.board.version: 1.0
dmi.chassis.type: 3
dmi.chassis.vendor: Google
dmi.ec.firmware.release: 0.0
dmi.modalias:
dmi:bvncoreboot:bvrGoogle_Nocturne.10984.90.0:bd06/04/2019:br4.0:efr0.0:svnGoogle:pnNocturne:pvr1.0:rvnGoogle:rnNocturne:rvr1.0:cvnGoogle:ct3:cvr:
dmi.product.family: Google_Nocturne
dmi.product.name: Nocturne
dmi.product.version: 1.0
dmi.sys.vendor: Google
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