Backlight adjustment doesn't work on Google Pixel Slate
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux (Ubuntu) |
Confirmed
|
Undecided
|
Unassigned |
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:/
Discussion of issue & solution: https:/
This can be fixed with a simple patch which I have applied successfully to mainline 5.9-rc5: https:/
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-
ProcVersionSign
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:
CasperMD5CheckR
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-
PATH=(custom, no user)
LANG=en_US.UTF-8
SHELL=/bin/bash
ProcFB: 0 i915drmfb
ProcKernelCmdLine: BOOT_IMAGE=
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.
RelatedPackageV
linux-
linux-
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_
dmi.board.name: Nocturne
dmi.board.vendor: Google
dmi.board.version: 1.0
dmi.chassis.type: 3
dmi.chassis.vendor: Google
dmi.ec.
dmi.modalias: dmi:bvncoreboot
dmi.product.family: Google_Nocturne
dmi.product.name: Nocturne
dmi.product.
dmi.sys.vendor: Google
tags: | added: patch |
This change was made by a bot.