[Lenovo FLex 2] Display backlight does not reduce after checking 'Dim screen to save power'

[Sayantan Das]

Hi,

I am using Ubuntu 14.04.1 LTS on Lenovo FLex 2. The laptop display backlight does not reduce even after selecting 'Dim screen to save power' in the Battery Setttings.
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ApportVersion: 2.14.1-0ubuntu3.2
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: sayantan 2009 F.... pulseaudio
 /dev/snd/controlC1: sayantan 2009 F.... pulseaudio
CurrentDesktop: Unity
DistroRelease: Ubuntu 14.04
HibernationDevice: RESUME=UUID=ccdc92e5-9c8d-4e92-93d6-a300e775615b
InstallationDate: Installed on 2014-07-28 (5 days ago)
InstallationMedia: Ubuntu 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.2)
Lsusb:
 Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
 Bus 001 Device 004: ID 04f3:0333 Elan Microelectronics Corp.
 Bus 001 Device 003: ID 0bda:b728 Realtek Semiconductor Corp.
 Bus 001 Device 002: ID 5986:055e Acer, Inc
 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
MachineType: LENOVO 20404
Package: linux (not installed)
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-32-generic.efi.signed root=UUID=0705e595-a4d7-4cc8-8976-e8692f30f49e ro quiet splash vt.handoff=7
ProcVersionSignature: Ubuntu 3.13.0-32.57-generic 3.13.11.4
RelatedPackageVersions:
 linux-restricted-modules-3.13.0-32-generic N/A
 linux-backports-modules-3.13.0-32-generic N/A
 linux-firmware 1.127.5
Tags: trusty
Uname: Linux 3.13.0-32-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo
_MarkForUpload: True
dmi.bios.date: 03/21/2014
dmi.bios.vendor: LENOVO
dmi.bios.version: A0CN21WW
dmi.board.asset.tag: No Asset Tag
dmi.board.name: Lenovo Flex 2-14
dmi.board.vendor: LENOVO
dmi.board.version: 31900059 Std
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Lenovo Flex 2-14
dmi.modalias: dmi:bvnLENOVO:bvrA0CN21WW:bd03/21/2014:svnLENOVO:pn20404:pvrLenovoFlex2-14:rvnLENOVO:rnLenovoFlex2-14:rvr31900059Std:cvnLENOVO:ct10:cvrLenovoFlex2-14:
dmi.product.name: 20404
dmi.product.version: Lenovo Flex 2-14
dmi.sys.vendor: LENOVO

[Sayantan Das (sayantan13)]

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[Sayantan Das (sayantan13)]

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[Sayantan Das (sayantan13)]

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[Sayantan Das (sayantan13)]

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[Sayantan Das (sayantan13)]

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[Sayantan Das (sayantan13)]

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[Sayantan Das (sayantan13)]

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[Sayantan Das (sayantan13)]

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[Sayantan Das (sayantan13)]

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[Sayantan Das (sayantan13)]

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[Sayantan Das (sayantan13)]

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[Sayantan Das (sayantan13)]

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[Sayantan Das (sayantan13)]

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[Sayantan Das (sayantan13)]

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[Sayantan Das (sayantan13)]

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[Brad Figg (brad-figg)]

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 v3.17 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'.

If you are unable to test the mainline kernel, for example it will not boot, please add the tag: 'kernel-unable-to-test-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/v3.17-rc1-utopic/

[Sayantan Das (sayantan13)]

Hi,

I have tested this with the latest kernel.

flex2:~$ uname -a
Linux flex2 3.17.0-031700rc1-generic #201408161335 SMP Sat Aug 16 17:36:29 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

This bug is still present . THe screen does not automatically dim when power source is removed and laptop runs on battery.

[Yung Shen (kaxing)]

I've also noticed this situation. But I think it's not really a bug but a confused change made in power settings.

@sayantan13 can you check if you can also see the same results:

Steps to verify:

1. check "Dim screen to save power"

2. in "Turn screen off when inactive for", select "2 minutes"

And then wait for the system goes to inactive, you should see result with follow progress:

normal -> system goes inactive (0s) -> screen dim at 30% backlight (1:30s) -> screen starting dimming again (1:50s) until black/off.

If you cannot see it dimming but it still goes to black screen, not could possibility your backlight does not work at first place.