Samsung N310 screen luminosity/brightness flickers randomly

[Stéphane Guillou]

This bug started around 3 weeks ago on my Samsung N310 netbook. I run updates at least every two days. I never had any problem with luminosity before then (2 years of using this netbook with several Ubuntu versions).

I'm on Ubuntu 12.04 LTS 32 bits up to date.

What I witness:
- Often, at boot up, the luminosity flickers heavily. I can not use my computer (clicking doesn't respond) until I play with the luminosity keyboard shortcuts.
- Sometimes, it happens in the middle of a session. I can't figure out what triggers it.
- I also noticed that, often, I can only choose between full luminosity, backscreen off or minimum luminosity. The intermediate levels are not available (the cursor of the OSD bubble goes automatically all the way to the top or to the bottom).

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: linux-image-3.2.0-29-generic-pae 3.2.0-29.46
ProcVersionSignature: Ubuntu 3.2.0-29.46-generic-pae 3.2.24
Uname: Linux 3.2.0-29-generic-pae i686
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24.
AplayDevices:
 **** List of PLAYBACK Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: ALC272 Analog [ALC272 Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
ApportVersion: 2.0.1-0ubuntu12
Architecture: i386
ArecordDevices:
 **** List of CAPTURE Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: ALC272 Analog [ALC272 Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: chtfn 1725 F.... pulseaudio
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xf0340000 irq 43'
   Mixer name : 'Realtek ALC272'
   Components : 'HDA:10ec0272,144dc052,00100001'
   Controls : 21
   Simple ctrls : 12
Date: Thu Aug 2 11:05:54 2012
HibernationDevice: RESUME=UUID=ea74f8fe-3964-4530-a377-542c052c94ec
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Beta i386 (20120328)
MachineType: SAMSUNG ELECTRONICS CO., LTD. N310
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.2.0-29-generic-pae root=UUID=d32fcecd-4a85-4801-9be4-2dfe9bd1f769 ro quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.2.0-29-generic-pae N/A
 linux-backports-modules-3.2.0-29-generic-pae N/A
 linux-firmware 1.79
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
WifiSyslog:

dmi.bios.date: 01/13/2010
dmi.bios.vendor: Phoenix Technologies Ltd.
dmi.bios.version: 06BA.M042.20100113.CYH
dmi.board.name: N310
dmi.board.vendor: SAMSUNG ELECTRONICS CO., LTD.
dmi.board.version: Not Applicable
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: SAMSUNG ELECTRONICS CO., LTD.
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnPhoenixTechnologiesLtd.:bvr06BA.M042.20100113.CYH:bd01/13/2010:svnSAMSUNGELECTRONICSCO.,LTD.:pnN310:pvrNotApplicable:rvnSAMSUNGELECTRONICSCO.,LTD.:rnN310:rvrNotApplicable:cvnSAMSUNGELECTRONICSCO.,LTD.:ct10:cvrN/A:
dmi.product.name: N310
dmi.product.version: Not Applicable
dmi.sys.vendor: SAMSUNG ELECTRONICS CO., LTD.