Backlight controls do not have any effect on a Macbook7,1 running Ubuntu 18.04.
Ubuntu is installed in Legacy BIOS mode and uses the proprietary Nvidia drivers.
The apple_backlight directory appears in /sys/class/backlight and while different brightness values can be set, they have no effect on the backlight's emitted brightness.
The backlight remains at full brightness.
I have tested the following kernel parameters but they have no effect.
acpi_backlight=vendor
video.use_bios_initial_backlight=0
acpi_osi=
video.use_native_backlight=1
---
ProblemType: Bug
ApportVersion: 2.20.9-0ubuntu7.23
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC0: jordan 1659 F.... pulseaudio
CurrentDesktop: Pantheon
DistroRelease: elementary OS 5.1.7
InstallationDate: Installed on 2021-01-30 (9 days ago)
InstallationMedia: elementary OS 5.1 "hera" - stable amd64 (20200814)
MachineType: Apple Inc. MacBook7,1
NonfreeKernelModules: nvidia wl
Package: linux (not installed)
ProcFB: 0 VESA VGA
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-5.4.0-65-generic root=UUID=6cdd2f7b-d747-4fbc-8062-317304a148a6 ro rootflags=subvol=@ quiet splash vt.handoff=1
ProcVersionSignature: Ubuntu 5.4.0-65.73~18.04.1-generic 5.4.78
RelatedPackageVersions:
linux-restricted-modules-5.4.0-65-generic N/A
linux-backports-modules-5.4.0-65-generic N/A
linux-firmware 1.173.19
Tags: hera
Uname: Linux 5.4.0-65-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: sudo
WifiSyslog:
_MarkForUpload: True
dmi.bios.date: 02/02/18
dmi.bios.vendor: Apple Inc.
dmi.bios.version: MB71.88Z.003F.B00.1802022149
dmi.board.name: Mac-F22C89C8
dmi.board.vendor: Apple Inc.
dmi.chassis.type: 10
dmi.chassis.vendor: Apple Inc.
dmi.chassis.version: Mac-F22C89C8
dmi.modalias: dmi:bvnAppleInc.:bvrMB71.88Z.003F.B00.1802022149:bd02/02/18:svnAppleInc.:pnMacBook7,1:pvr1.0:rvnAppleInc.:rnMac-F22C89C8:rvr:cvnAppleInc.:ct10:cvrMac-F22C89C8:
dmi.product.family: MacBook
dmi.product.name: MacBook7,1
dmi.product.version: 1.0
dmi.sys.vendor: Apple Inc.
This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:
apport-collect 1915082
and then change the status of the bug to 'Confirmed'.
If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.
This change has been made by an automated script, maintained by the Ubuntu Kernel Team.