8086:27ae [Acer AOA110] backlight too bright, can't dim it much

[Thindi]

Screen is far too bright, dims only slightly with hotkeys, brightness control applet ineffective. Tried more than half a dozen solutions (incl. editing the grub which used to work fine with Ubuntu 12.04) but none of them worked.

thindi@thindi-AOA110:~$ ls /sys/class/backlight > backlight
thindi@thindi-AOA110:~$ grep -r . /proc/acpi > acpi
grep: /proc/acpi/event: Permission denied
thindi@thindi-AOA110:~$ sudo acpidump -o acpidump.txt
thindi@thindi-AOA110:~$ acpixtract acpidump.txt
Acpi table [DSDT] - 24038 bytes written to DSDT.dat
Acpi table [SSDT] - 1220 bytes written to SSDT.dat
thindi@thindi-AOA110:~$ iasl -d DSDT.dat

Intel ACPI Component Architecture
AML Disassembler version 20100528 [Dec 19 2012]
Copyright (c) 2000 - 2010 Intel Corporation
Supports ACPI Specification Revision 4.0a

Loading Acpi table from file DSDT.dat
Acpi table [DSDT] successfully installed and loaded
Pass 1 parse of [DSDT]
Pass 2 parse of [DSDT]
Parsing Deferred Opcodes (Methods/Buffers/Packages/Regions)
...................................................................................................................................................................................................................................................................................................................................................................
Parsing completed
Disassembly completed, written to "DSDT.dsl"
sudo fwts > fwts
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1258495/+attachment/3931116/+files/fwts

thindi@thindi-AOA110:~$ dmesg | grep 'ACPI: Video' > video
thindi@thindi-AOA110:~$ sudo dmidecode > dmidecode.log
thindi@thindi-AOA110:~$ cat /proc/version > version

Reboot with only the kernel parameter acpi_backlight=vendor:
If that means the grub file (excerpt) should look like this:
GRUB_DEFAULT=0
GRUB_HIDDEN_TIMEOUT=0
GRUB_HIDDEN_TIMEOUT_QUIET=true
GRUB_TIMEOUT=10
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="acpi_backlight=vendor"
GRUB_CMDLINE_LINUX=""

Make a comment on if you can now alter the backlight with hotkeys or a brightness applet.
Neither do the job.

thindi@thindi-AOA110:~$ ls /sys/class/backlight > vendorbacklight
thindi@thindi-AOA110:~$ sudo su
root@thindi-AOA110:/home/thindi# ls -la /sys/class/backlight/intel_backlight/ > lslabacklight
root@thindi-AOA110:/home/thindi# echo 8 > /sys/class/backlight/intel_backlight/brightness
No change after doing that.

o "Reboot with kernel parameter video.use_bios_initial_backlight=0"

Don't know how to do that.

Dealing with the rest on this site https://wiki.ubuntu.com/Kernel/Debugging/Backlight is out of my depth.

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: linux-image-3.11.0-14-generic 3.11.0-14.21
ProcVersionSignature: Ubuntu 3.11.0-14.21-generic 3.11.7
Uname: Linux 3.11.0-14-generic i686
ApportVersion: 2.12.5-0ubuntu2.1
Architecture: i386
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: thindi 1586 F.... pulseaudio
 /dev/snd/pcmC0D0p: thindi 1586 F...m pulseaudio
Date: Fri Dec 6 11:31:38 2013
HibernationDevice: RESUME=UUID=9793476b-8516-4e8d-b628-0dd0389b1376
InstallationDate: Installed on 2013-12-03 (3 days ago)
InstallationMedia: Ubuntu 13.10 "Saucy Salamander" - Release i386 (20131016.1)
MachineType: Acer AOA110
MarkForUpload: True
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.11.0-14-generic root=UUID=bf6adaec-4e58-4748-95d7-8d287f559046 ro quiet splash pcie_aspm=force acpi_backlight=vendor vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.11.0-14-generic N/A
 linux-backports-modules-3.11.0-14-generic N/A
 linux-firmware 1.116
RfKill:
 0: phy0: Wireless LAN
  Soft blocked: no
  Hard blocked: no
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 10/06/2008
dmi.bios.vendor: Acer
dmi.bios.version: v0.3309
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.vendor: Acer
dmi.board.version: Base Board Version
dmi.chassis.type: 1
dmi.chassis.vendor: Chassis Manufacturer
dmi.chassis.version: Chassis Version
dmi.modalias: dmi:bvnAcer:bvrv0.3309:bd10/06/2008:svnAcer:pnAOA110:pvr1:rvnAcer:rn:rvrBaseBoardVersion:cvnChassisManufacturer:ct1:cvrChassisVersion:
dmi.product.name: AOA110
dmi.product.version: 1
dmi.sys.vendor: Acer

[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 v3.12 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/v3.13-rc3-trusty/

[Thindi (xmastrees)]

Hi there,

Thanks a lot for the reply. Before I tried your suggestions, I got a system problem message, so just to be safe I did a fresh install of Ubuntu 13.10, tested the backlight (still the same issue),
then installed
linux-image-3.12.0-031200-generic_3.12.0-031200.201311031935_i386.deb (as you mentioned v3.12), tested the backlight, no change.
After that I did a fresh install again (no change in the backlight issue) to install
linux-image-3.13.0-031300rc3-generic_3.13.0-031300rc3.201312061335_i386.deb (because you linked to v3.13) but the problem still persists.

In neither versions I could see them being mentioned in the boot menu, so does this count as 'kernel-unable-to-test-upstream'?

During the boot with the latter version there were two messages, the first one being:
"[ 0.000000] tsc: Fast TSC calibration failed"
I couldn't capture the second message as it was too long and disappeared too quickly (if you really need to know what it said, then I could try to find out anyway, maybe if you could tell me how to freeze the message for long enough?).
Those messages turned from white to yellow font and then Ubuntu booted up fine (well, after some boots the clock and 'shut down' buttons were missing).

Please let me know if I can do anything else to help solve this issue.

Thanks again!

Christine

> Date: Fri, 6 Dec 2013 20:23:09 +0000
> From: <email address hidden>
> To: <email address hidden>
> Subject: [Bug 1258495] Re: backlight too bright, can't dim it much
>
> Would it be possible for you to test the latest upstream kernel? Refer
> to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest
> v3.12 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/v3.13-rc3-trusty/
>
>
> ** Changed in: linux (Ubuntu)
> Importance: Undecided => Medium
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1258495
>
> Title:
> backlight too bright, can't dim it much
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1258495/+subscriptions

[penalvch (penalvch)]

Cut from Bug Description.

[penalvch (penalvch)]

Thindi, as per http://us.acer.com/ac/en/US/content/drivers an update is available for your BIOS (3310). If you update to this following https://help.ubuntu.com/community/BiosUpdate , does it change anything? If it doesn't, could you please both specify what happened, and just provide the output of the following terminal command:
sudo dmidecode -s bios-version && sudo dmidecode -s bios-release-date

Please note your current BIOS is already in the Bug Description, so posting this on the old BIOS would not be helpful.

For more on BIOS updates and linux, please see https://help.ubuntu.com/community/ReportingBugs#Bug_reporting_etiquette .

Thank you for your understanding.

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]