Backlight control does not work on linux mint - acer aspire 5741

[matti]

Backlight control does not work, but there are entries in /sys/class/backlight

System: linux Mint 16 on Acer Aspire 5741

I will follow the debugging method on: https://wiki.ubuntu.com/Kernel/Debugging/Backlight

1) ls /sys/class/backlight
 acer-wmi intel_backlight

2) grep -r . /proc/acpi
 /proc/acpi/button/lid/LID0/state:state: open
grep: /proc/acpi/event: Dispositivo o risorsa occupata
/proc/acpi/wakeup:Device S-state Status Sysfs node
/proc/acpi/wakeup:AZAL S3 *disabled pci:0000:00:1b.0
/proc/acpi/wakeup:P0P1 S4 *disabled pci:0000:00:1e.0
/proc/acpi/wakeup:EHC1 S3 *enabled pci:0000:00:1d.0
/proc/acpi/wakeup:USB1 S3 *disabled
/proc/acpi/wakeup:USB2 S3 *disabled
/proc/acpi/wakeup:USB3 S3 *disabled
/proc/acpi/wakeup:USB4 S3 *disabled
/proc/acpi/wakeup:USB5 S3 *disabled
/proc/acpi/wakeup:USB6 S3 *disabled
/proc/acpi/wakeup:USB7 S3 *disabled
/proc/acpi/wakeup:RP01 S4 *disabled pci:0000:00:1c.0
/proc/acpi/wakeup:PEG5 S4 *disabled

3) dmesg | grep 'ACPI: Video' > video
[ 8.291555] ACPI: Video Device [GFX0] (multi-head: yes rom: yes post: no)

4)/proc/version
Linux version 3.11.0-12-generic (buildd@allspice) (gcc version 4.8.1 (Ubuntu/Linaro 4.8.1-10ubuntu7) ) #19-Ubuntu SMP Wed Oct 9 16:20:46 UTC 2013

5) reboot with only the kernel parameter acpi_backlight=vendor
now its disappeared also the OSD info

6)ls -la /sys/class/backlight/intel_backlight
lrwxrwxrwx 1 root root 0 gen 23 23:56 /sys/class/backlight/intel_backlight -> ../../devices/pci0000:00/0000:00:02.0/drm/card0/card0-LVDS-1/intel_backlight

7)Reboot with just kernel parameter video.use_bios_initial_backlight=0
nothing change (but the OSD is returned)

8) echo 8 | sudo tee /sys/class/backlight/intel_backlight/brightness
it's works..

9)showkey -s
fn+left (0x...)
e0 4c e0 cc
e0 56 e0 d6

fn+right (0x...)
e0 54 e0 d4

10) ... any ideas?

ps: i've attached the intel acpi info DTDT.dsl

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: linux-image-3.11.0-12-generic 3.11.0-12.19
ProcVersionSignature: Ubuntu 3.11.0-12.19-generic 3.11.3
Uname: Linux 3.11.0-12-generic x86_64
ApportVersion: 2.12.5-0ubuntu2.2
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: tia 1844 F.... pulseaudio
Date: Fri Jan 24 00:25:00 2014
HibernationDevice: RESUME=UUID=1f0244d2-61fe-4fd4-9a24-f425d6811bf2
InstallationDate: Installed on 2014-01-23 (0 days ago)
InstallationMedia: Linux Mint 16 "petra" - Release amd64 20131126
MachineType: Acer Aspire 5741
MarkForUpload: True
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=it_IT.UTF-8
 SHELL=/bin/bash
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.11.0-12-generic root=UUID=13480b77-86cb-4a3d-b2ea-a4006b469683 ro quiet splash acpi_backlight=vendor vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.11.0-12-generic N/A
 linux-backports-modules-3.11.0-12-generic N/A
 linux-firmware 1.116
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 04/22/2010
dmi.bios.vendor: Acer
dmi.bios.version: V1.06
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: Aspire 5741
dmi.board.vendor: Acer
dmi.board.version: V1.06
dmi.chassis.type: 10
dmi.chassis.vendor: Acer
dmi.chassis.version: V1.06
dmi.modalias: dmi:bvnAcer:bvrV1.06:bd04/22/2010:svnAcer:pnAspire5741:pvrV1.06:rvnAcer:rnAspire5741:rvrV1.06:cvnAcer:ct10:cvrV1.06:
dmi.product.name: Aspire 5741
dmi.product.version: V1.06
dmi.sys.vendor: Acer

[Brad Figg (brad-figg)]

This change was made by a bot.

[Andy Whitcroft (apw)]

This kernel version 3.11.0-12 is pretty old, looking at the commits since there have been a number of backlight related fixes. Could you update to the latest kernel and confirm it is still present.

[Launchpad Janitor (janitor)]

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