Public bug reported:
Please see the full description on:
http://ubuntuforums.org/showthread.php?t=2216224&page=2
I posted on ubuntu forum after trying numerous ineffective solutions to
a backlight auto-dimming issue. After running through a troubleshooting
process which is described on the page linked above, I was advised by
Toz to submit a kernel bug.
sudo dmidecode -s system-manufacturer
SAMSUNG ELECTRONICS CO., LTD.
sudo dmidecode -s system-product-name
700T1C
sudo dmidecode -s system-version
P10AAT
sudo modprobe samsung_laptop
modprobe: ERROR: could not insert 'samsung_laptop': No such device
cat /proc/cmdline
BOOT_IMAGE=/vmlinuz-3.16.0-31-generic.efi.signed
root=/dev/mapper/ubuntu--vg-root ro acpi_osi=Linux quiet splash vt.handoff=7
lsb_release -rd
Description: Ubuntu 14.04.2 LTS
Release: 14.04
Summary:
I can't control the brightness from my settings or by manually changing the
values in ../intel_backlight/brightness.
My auto brightness seems to have a mind of its own and unfortunately for me I
can't fix it with the "acpi_osi=" trick. Since the auto brightness flickers up
and down every few seconds, its so frustrating that I can barely use my tablet.
I tried my best to fix in the last 4 days since I re-installed Ubuntu, but
regardless of what I tried, I simply can't stabilize it, nevermind control it.
At this state I would be delighted if I could just set it to one value at boot.
After running a few commands as advised by Toz, the flickering seems to
have stopped while the tablet is plugged in, but while the settings
value shows my screen at max brightness, its definitely not as bright as
in Windows. (and I definitely don't want to use Windows as my main OS).
I would like to be able to control the brightness manually in the power
settings or by setting it at boot in rc.local.
PS: btw the controls for gyro, accelometer and rotation don't seem to be
functional in Ubuntu, even if they show up in lsmod as loaded. Could
these be because of the missing samsung_laptop module?
I hope this helps. If you require further info, please get in touch.
Thanks!
ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: linux-image-3.16.0-31-generic 3.16.0-31.43~14.04.1
ProcVersionSignature: Ubuntu 3.16.0-31.43~14.04.1-generic 3.16.7-ckt5
Uname: Linux 3.16.0-31-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.7
Architecture: amd64
CurrentDesktop: Unity
Date: Wed Mar 18 03:05:42 2015
EcryptfsInUse: Yes
InstallationDate: Installed on 2015-03-11 (6 days ago)
InstallationMedia: Ubuntu 14.04.2 LTS "Trusty Tahr" - Release amd64 (20150218.1)
SourcePackage: linux-lts-utopic
UpgradeStatus: No upgrade log present (probably fresh install)
** Affects: linux-lts-utopic (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug trusty
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https://bugs.launchpad.net/bugs/1433410
Title:
Auto backlight control. Modprobe samsung_laptop returns "ERROR...No
such device" on Samsung XE700T
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