[Dell Vostro 5470] Unable to control brightness

[Po-Hsu Lin]

CID: 201307-14037 Vostro 5470

Brightness control does not work on this system
The brightness level indicator would change with hotkey events, but the brightness itself does not.

There is a simliar bug reported before, bug 1333638 for 201307-14038, another Vostro 5470, but the brightness control works on that system because it has a discrete video card. For this UMA system, it doesn't work.

== WORKAROUND ==
Brightness would work with "acpi_osi=\"!Windows 2012\"" added to grub.
Also verified on 201307-14038, this workaround won't affect its brightness control capability.

Debugging information:
ubuntu@201307-14037:~$ ls /sys/class/backlight
acpi_video0 intel_backlight

ubuntu@201307-14037:~$ grep -r . /proc/acpi
/proc/acpi/battery/BAT0/alarm:alarm: unsupported
/proc/acpi/battery/BAT0/state:present: yes
/proc/acpi/battery/BAT0/state:capacity state: ok
/proc/acpi/battery/BAT0/state:charging state: charged
/proc/acpi/battery/BAT0/state:present rate: 1 mA
/proc/acpi/battery/BAT0/state:remaining capacity: 4412 mAh
/proc/acpi/battery/BAT0/state:present voltage: 12493 mV
/proc/acpi/battery/BAT0/info:present: yes
/proc/acpi/battery/BAT0/info:design capacity: 4520 mAh
/proc/acpi/battery/BAT0/info:last full capacity: 4412 mAh
/proc/acpi/battery/BAT0/info:battery technology: non-rechargeable
/proc/acpi/battery/BAT0/info:design voltage: 11100 mV
/proc/acpi/battery/BAT0/info:design capacity warning: 441 mAh
/proc/acpi/battery/BAT0/info:design capacity low: 0 mAh
/proc/acpi/battery/BAT0/info:cycle count: 0
/proc/acpi/battery/BAT0/info:capacity granularity 1: 100 mAh
/proc/acpi/battery/BAT0/info:capacity granularity 2: 0 mAh
/proc/acpi/battery/BAT0/info:model number: Dell
/proc/acpi/battery/BAT0/info:serial number: 716
/proc/acpi/battery/BAT0/info:battery type: LION
/proc/acpi/battery/BAT0/info:OEM info: SIMPLO
/proc/acpi/button/lid/LID0/state:state: open
/proc/acpi/ac_adapter/ADP0/state:state: on-line
/proc/acpi/wakeup:Device S-state Status Sysfs node
/proc/acpi/wakeup:P0P1 S4 *disabled
/proc/acpi/wakeup:GLAN S4 *disabled
/proc/acpi/wakeup:EHC1 S4 *enabled pci:0000:00:1d.0
/proc/acpi/wakeup:EHC2 S4 *disabled
/proc/acpi/wakeup:XHC S4 *enabled pci:0000:00:14.0
/proc/acpi/wakeup:HDEF S4 *disabled pci:0000:00:1b.0
/proc/acpi/wakeup:RP01 S4 *disabled pci:0000:00:1c.0
/proc/acpi/wakeup:PXSX S4 *disabled
/proc/acpi/wakeup:RP02 S4 *disabled pci:0000:00:1c.1
/proc/acpi/wakeup:PXSX S4 *disabled pci:0000:02:00.0
/proc/acpi/wakeup:RP03 S4 *disabled pci:0000:00:1c.2
/proc/acpi/wakeup:PXSX S4 *enabled pci:0000:07:00.0
/proc/acpi/wakeup:RP04 S4 *disabled pci:0000:00:1c.3
/proc/acpi/wakeup:PXSX S4 *disabled pci:0000:08:00.0
/proc/acpi/wakeup:PEG0 S4 *disabled
/proc/acpi/wakeup:PEGP S4 *disabled
/proc/acpi/wakeup:PEG1 S4 *disabled
/proc/acpi/wakeup:PEG2 S4 *disabled
/proc/acpi/wakeup:LID0 S3 *enabled

ubuntu@201307-14037:~$ dmesg | grep 'ACPI: Video'
[ 12.591778] ACPI: Video Device [GFX0] (multi-head: yes rom: no post: no)
ubuntu@201307-14037:~$

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: linux-image-3.13.0-43-generic 3.13.0-43.72
ProcVersionSignature: Ubuntu 3.13.0-43.72-generic 3.13.11.11
Uname: Linux 3.13.0-43-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.6
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: ubuntu 1458 F.... pulseaudio
 /dev/snd/controlC1: ubuntu 1458 F.... pulseaudio
CRDA:
 country TW:
  (2402 - 2472 @ 40), (3, 27)
  (5270 - 5330 @ 40), (3, 17), DFS
  (5735 - 5815 @ 40), (3, 30)
CurrentDesktop: Unity
Date: Thu Jan 8 04:06:09 2015
HibernationDevice: RESUME=UUID=2bba8b6d-4818-4d59-8187-613dffbe1088
InstallationDate: Installed on 2014-12-29 (9 days ago)
InstallationMedia: Ubuntu 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.2)
MachineType: Dell Inc. Vostro 5470
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-43-generic root=UUID=b23b072b-a0ef-48de-bc97-3d66100bbc82 ro quiet splash "acpi_osi=!Windows 2012" vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.13.0-43-generic N/A
 linux-backports-modules-3.13.0-43-generic N/A
 linux-firmware 1.127.11
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 08/23/2013
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A01
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: White Tip Mountain
dmi.board.vendor: Intel Corp.
dmi.board.version: FAB3
dmi.chassis.asset.tag: Asset Tag
dmi.chassis.type: 9
dmi.chassis.vendor: Intel Corporation
dmi.chassis.version: 0.1
dmi.modalias: dmi:bvnDellInc.:bvrA01:bd08/23/2013:svnDellInc.:pnVostro5470:pvr:rvnIntelCorp.:rnWhiteTipMountain:rvrFAB3:cvnIntelCorporation:ct9:cvr0.1:
dmi.product.name: Vostro 5470
dmi.sys.vendor: Dell Inc.

[Brad Figg (brad-figg)]

This change was made by a bot.