current boot config dims screen during initramfs

[Tessa]

This is a weird one. Shortly after moving to 17.10, my laptop has started dimming its internal screen to minimum brightness at the start of initramfs execution. shortly thereafter it restores it to normal brightness, but that only happens *after* typing in encrypted filesystem passwords, so the password dialogues are practically invisible. Not sure why its doing this, but whatever's restoring the brightness should do it before prompting for filesystem mounting so these prompts are actually visible.

ProblemType: Bug
DistroRelease: Ubuntu 17.10
Package: linux-generic 4.13.0.19.20
ProcVersionSignature: Ubuntu 4.13.0-19.22-generic 4.13.13
Uname: Linux 4.13.0-19-generic x86_64
NonfreeKernelModules: zfs zunicode zavl zcommon znvpair
ApportVersion: 2.20.7-0ubuntu3.6
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: tessa 17026 F.... pulseaudio
 /dev/snd/controlC1: tessa 17026 F.... pulseaudio
CurrentDesktop: GNOME
Date: Fri Dec 15 13:44:02 2017
InstallationDate: Installed on 2016-07-08 (524 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
MachineType: Apple Inc. MacBookPro11,4
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.13.0-19-generic.efi.signed root=ZFS=rpool/root ro quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-4.13.0-19-generic N/A
 linux-backports-modules-4.13.0-19-generic N/A
 linux-firmware 1.169.1
SourcePackage: linux
UpgradeStatus: Upgraded to artful on 2017-10-19 (57 days ago)
dmi.bios.date: 08/08/2017
dmi.bios.vendor: Apple Inc.
dmi.bios.version: MBP114.88Z.0177.B00.1708080033
dmi.board.name: Mac-06F11FD93F0323C5
dmi.board.vendor: Apple Inc.
dmi.board.version: MacBookPro11,4
dmi.chassis.type: 9
dmi.chassis.vendor: Apple Inc.
dmi.chassis.version: Mac-06F11FD93F0323C5
dmi.modalias: dmi:bvnAppleInc.:bvrMBP114.88Z.0177.B00.1708080033:bd08/08/2017:svnAppleInc.:pnMacBookPro11,4:pvr1.0:rvnAppleInc.:rnMac-06F11FD93F0323C5:rvrMacBookPro11,4:cvnAppleInc.:ct9:cvrMac-06F11FD93F0323C5:
dmi.product.family: MacBook Pro
dmi.product.name: MacBookPro11,4
dmi.product.version: 1.0
dmi.sys.vendor: Apple Inc.

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

This change was made by a bot.

[Joseph Salisbury (jsalisbury)]

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v4.15 kernel[0].

If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'.

Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".

Thanks in advance.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.15-rc4

[Tessa (unit3)]

Unfortunately I can't test with the upstream kernel, as I'm using a ZFS root vol and the ZFS modules don't build against that kernel.

[Kai-Heng Feng (kaihengfeng)]

That's because rootfs has systemd-backlight@.service to restore/save the brightness value. Probably a good idea to do the same for initramfs.