I Run Ubuntu on a Samsung N150+ netbook.
I have recently updated Ubuntu (to 13.04) and now the backlight control doesn't work...
If I start up with the mains pluged in the screen comes up bright enough to see clearly, but if I start up on battery power the screen is so dim I can barely see what I am doing. Either way I cannot alter the screen brightness.
This is not an entirely new problem. When I first installed Ubuntu it didn't work and I found the following solution:
sudo add-apt-repository ppa:voria/ppa
sudo apt-get update && sudo apt-get upgrade
sudo apt-get install samsung-tools samsung-backlight
So, I have tried this again. With no effect.
I have discovered that under Settings/Software & Updates/Other software it says:
Disabled on upgrade to Oneric (http://ppa.launchpad.net/voria/ppa)
So I guess that is why the above no longer works.
In addition, some of the other Hotkeys (Eg. wifi/bluetooth/sound/screen on/off) all work.
This is currently causing big problems. I'm away from home, using my netbook as my primary form of comunication in cafes etc. My ability to find a wifi connection with a power supply is limited.
Work Around: I have just discovered that if I start on a power supply and then 'Hibernate' I will have a bright screen if I restart on battery power. But still no brightness control.
Other than reverting to backup (My backups are at home) does anyone have a solution?
I looked on the Ubuntu forums and found this thread:
Which might help me, if I understood it. I'm not very good with the technical side of Ubuntu, as it usually just works.
I then found this thread:
Which asked for the some comands to be run (for Diagnostics?):
1 Your current kernel command line:
2 Your video card and driver:
BOOT_IMAGE=/boot/vmlinuz-3.8.0-26-generic root=UUID=2a09def6-779f-4377-bf2d-72f44d877e5d ro quiet splash vt.handoff=7
sudo lspci -vnn | grep -A12 VGA
3 Your backlight interfaces:
00:02.0 VGA compatible controller : Intel Corporation Atom Processor D4xx/D5xx/N4xx/N5xx Integrated Graphics Controller [8086:a011] (prog-if 00 [VGA controller])
Subsystem: Samsung Electronics Co Ltd Notebook N150P [144d:c072]
Flags: bus master, fast devsel, latency 0, IRQ 46
Memory at f0300000 (32-bit, non-prefetchable) [size=512K]
I/O ports at 18d0 [size=8]
Memory at d0000000 (32-bit, prefetchable) [size=256M]
Memory at f0000000 (32-bit, non-prefetchable) [size=1M]
Expansion ROM at <unassigned> [disabled]
Capabilities:  MSI: Enable+ Count=1/1 Maskable- 64bit-
Capabilities: [d0] Power Management version 2
Kernel driver in use: i915
00:02.1 Display controller : Intel Corporation Atom Processor D4xx/D5xx/N4xx/N5xx Integrated Graphics Controller [8086:a012]
for i in /sys/class/backlight/*; do echo $i; cat $i/brightness; cat $i/max_brightness; done
So I have done likewise, in the hopes that they will be usefull...
I suspect that the first link above is probably the solution, if only I understood it.