The new (2.6.39+) samsung_laptop kernel module causes serious backlight flickering - makes the desktop unusable

[Felix Vollmer]

== SRU Justification ==

Impact: Many Samsung notebook models require a quirk for adjusting the screen brightness, but on some models the quirk detection fails and the wrong backlight adjustment method is used.

Fix: Upstream cherry pick to fix quirk detection.

Test Case: Verified on LP #810093 on the Samsung N220P.

---

*** Workaround in #26 ***
(A patched kernel module. Please test)
Original bug report:

I have a Samsung N220 plus. The backlight of the laptop often starts flickering (switching very fast between 2 brightness levels) when gnome tries to reduce the screen brightness (automatically after some time) to save power. This problem also occurs if you press more and less screen brightness at the same time.
I think it could be a problem with the sabi Bios interaction (samsung-laptop.c), because "linux on my samsung" also had this Problem with theier samsung-backlight module:
http://www.voria.org/forum/viewtopic.php?t=625&p=5148
and they solved it by interfacing the backlight via pci.
I tried to enable debug modus of samsung-laptop module, but I didn't get any more output on error. Dmesg only says (a lot of times):
ACPI: Failed to switch the brightness
I'll provide more informations if needed.

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: linux-image-3.0.0-5-generic 3.0.0-5.6
ProcVersionSignature: Ubuntu 3.0.0-5.6-generic 3.0.0-rc7
Uname: Linux 3.0.0-5-generic i686
NonfreeKernelModules: wl
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24.
AplayDevices:
 **** List of PLAYBACK Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: ALC269 Analog [ALC269 Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
Architecture: i386
ArecordDevices:
 **** List of CAPTURE Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: ALC269 Analog [ALC269 Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: flexxxv 1405 F.... pulseaudio
CRDA: Error: [Errno 2] Datei oder Verzeichnis nicht gefunden
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xf0400000 irq 47'
   Mixer name : 'Realtek ALC269'
   Components : 'HDA:10ec0269,144dc072,00100004'
   Controls : 14
   Simple ctrls : 9
Date: Wed Jul 13 20:56:28 2011
HibernationDevice: RESUME=UUID=9f00b9b2-337b-4462-8157-50d16690f634
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Alpha i386 (20110705.1)
MachineType: SAMSUNG ELECTRONICS CO., LTD. N150P/N210P/N220P
ProcEnviron:
 LANGUAGE=de:en
 PATH=(custom, user)
 LANG=de_DE.UTF-8
 LC_MESSAGES=de_DE.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.0.0-5-generic root=UUID=1f2007e5-9b44-4cb5-a64a-4c2bf8dbda42 ro quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.0.0-5-generic N/A
 linux-backports-modules-3.0.0-5-generic N/A
 linux-firmware 1.56
SourcePackage: linux
StagingDrivers: brcmsmac brcmutil
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 04/30/2010
dmi.bios.vendor: Phoenix Technologies Ltd.
dmi.bios.version: 01KY.M008.20100430.RHU
dmi.board.asset.tag: SAMSUNG
dmi.board.name: N150P/N210P/N220P
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.:bvr01KY.M008.20100430.RHU:bd04/30/2010:svnSAMSUNGELECTRONICSCO.,LTD.:pnN150P/N210P/N220P:pvrNotApplicable:rvnSAMSUNGELECTRONICSCO.,LTD.:rnN150P/N210P/N220P:rvrNotApplicable:cvnSAMSUNGELECTRONICSCO.,LTD.:ct10:cvrN/A:
dmi.product.name: N150P/N210P/N220P
dmi.product.version: Not Applicable
dmi.sys.vendor: SAMSUNG ELECTRONICS CO., LTD.

[papukaija (papukaija)]

This bug is caused by the new samsung_laptop kernel module which was introduced in kernel 2.6.39. I haven't found any documentation for it but it sems to be written for at least the netbooks. If the module is enabled, the flickering starts on desktop load and can be stopped by changing the baclight brigtness. However, the only available modes are 0%, 10%(estimate) and 100%. The two lowest values are too dark for my eyes and the full backlight uses too much battery power.

WORKAROUND:

Disable the kernel module by adding:

blacklist samsung_laptop

to : /etc/modprobe.d/blacklist.conf

[Brad Figg (brad-figg)]

Thank you for taking the time to file a bug report on this issue.

However, given the number of bugs that the Kernel Team receives during any development cycle it is impossible for us to review them all. Therefore, we occasionally resort to using automated bots to request further testing. This is such a request.

We have noted that there is a newer version of the development kernel currently in the release pocket than the one you tested when this issue was found. Please test again with the newer kernel and indicate in the bug if this issue still exists or not.

If the bug still exists, change the bug status from Incomplete to Confirmed. If the bug no longer exists, change the bug status from Incomplete to Fix Released.

Thank you for your help.

[Simon Watson (simon-m-watson)]

Confirmed still occurs on 3.0.0-11-generic #18

[Brad Figg (brad-figg)]

Thank you for taking the time to file a bug report on this issue.

However, given the number of bugs that the Kernel Team receives during any development cycle it is impossible for us to review them all. Therefore, we occasionally resort to using automated bots to request further testing. This is such a request.

We have noted that there is a newer version of the development kernel than the one you last tested when this issue was found. Please test again with the newer kernel and indicate in the bug if this issue still exists or not.

If the bug still exists, change the bug status from Incomplete to Confirmed. If the bug no longer exists, change the bug status from Incomplete to Fix Released.

Thank you for your help, we really do appreciate it.

[Felix Vollmer (felixvollmer)]

I can confirm that this bug still exists in Kernel 3.0.0-11-generic. The behaviour is like papukaija said. It is pretty annoying and blacklisting the module isn't a real workaround, because you won't have any control over backlight. Only workaround I know is installing https://launchpad.net/~voria/+archive/ppa. I hope this will get fixed in some future release.

[Felix Vollmer (felixvollmer)]

sry, the 3.0.0-11 kernel is of cause the 3.0.0.11.18 kernel

[Brad Figg (brad-figg)]

Thank you for taking the time to file a bug report on this issue.

However, given the number of bugs that the Kernel Team receives during any development cycle it is impossible for us to review them all. Therefore, we occasionally resort to using automated bots to request further testing. This is such a request.

We have noted that there is a newer version of the development kernel than the one you last tested when this issue was found. Please test again with the newer kernel and indicate in the bug if this issue still exists or not.

If the bug still exists, change the bug status from Incomplete to Confirmed. If the bug no longer exists, change the bug status from Incomplete to Fix Released.

Thank you for your help, we really do appreciate it.

[Felix Vollmer (felixvollmer)]

I can confirm that the bug still exists in 3.0.0-12.19

[Brad Figg (brad-figg)]

Thank you for taking the time to file a bug report on this issue.

However, given the number of bugs that the Kernel Team receives during any development cycle it is impossible for us to review them all. Therefore, we occasionally resort to using automated bots to request further testing. This is such a request.

We have noted that there is a newer version of the development kernel than the one you last tested when this issue was found. Please test again with the newer kernel and indicate in the bug if this issue still exists or not.

If the bug still exists, change the bug status from Incomplete to Confirmed. If the bug no longer exists, change the bug status from Incomplete to Fix Released.

Thank you for your help, we really do appreciate it.

[Felix Vollmer (felixvollmer)]

I can confirm this too.
There is some talk about this issue on LKLM. I tried a patch for min max corrections, but it didn't help. I'll take a look at these patches later:
http://git.kernel.org/?p=linux/kernel/git/gregkh/patches.git;a=tree

[Felix Vollmer (felixvollmer)]

Hey I got this working :D
I applied:
platform-samsung_laptop-fix-samsung-brightness-min-max-calculations.patch
platform-brightness-quirk-for-samsung-laptop-driver.patch
from:
http://git.kernel.org/?p=linux/kernel/git/gregkh/patches.git;a=tree
and recompiled the modules.
Probatly it is a good Idea to use the other patches too.
I think this fix should make it to 11.10 release. Anyone here knows how to do this?
I add the two patches (credits go to Greg Kroah-Hartman (<email address hidden>) ) and my compiled binary module for people who don't want to compile themselves.

[Felix Vollmer (felixvollmer)]

Sry I can't figure out how to add more than one attachment

[Felix Vollmer (felixvollmer)]

and here the binary

[Felix Vollmer (felixvollmer)]

ok here is the real patch. sry. this is the diff between my patched samsung-laptop.c and the original samsung-laptop.c. Credits go to Greg Kroah-Hartman.

[Brendan Donegan (brendan-donegan)]

Set importance to High for Flexxxv since this issue is making any system with the affected hardware unusable.

[Joseph Salisbury (jsalisbury)]

Would it be possible for you to test the latest upstream kernel? It will allow additional upstream developers to examine the issue. Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Once you've tested the upstream kernel, please remove the 'needs-upstream-testing' tag. This can be done by clicking on the yellow pencil icon next to the tag located at the bottom of the bug description and deleting the 'needs-upstream-testing' text. Please let us know your results.

Thanks in advance.

[Felix Vollmer (felixvollmer)]

I installed the RC9 and the daily 3.1 kernel. For some reason I was unable to do a normal boot (boot just freezes with new kernel just like in this bug report: https://bugs.launchpad.net/ubuntu/+source/lightdm/+bug/856810). So I testet it in Safe-Mode (modprobe samsung-laptop, echo number > /sys/devices/platform/samsung/backlight/samsung/brightness ). Result:
The driver is still broken. Here is a quote from Greg Kroah-Hartman who describes the bug:
[quote]
On some Samsung laptops the brightness regulation works slightly different.
All SABI commands except for set_brightness work as expected. The behaviour
of set_brightness is as follows:

- Setting a new brightness will only step one level toward the new brightness
  level. For example, setting a level of 5 when the current level is 2 will
  result in a brightness level of 3.
- A spurious KEY_BRIGHTNESS_UP or KEY_BRIGHTNESS_DOWN event is also generated
  along with the change in brightness.
- Neither of the above two issues occur when changing from/to brightness
  level 0.
[/quote]

The patch in #15 are two of his patches that fix the backlight bug here. (I patched samsung-laptop and did a diff against the original from linux-source)

[Fortunato Ventre (voria)]

I've tested the patches from Greg Kroah-Hartman git repository on my Samsung NC10.
They work most of the time, but randomly they fail.

I've written 2 patches that fix the problem and I've already sent them to Greg. I will attach them here too.

[Fortunato Ventre (voria)]

Sometimes, while the function "check_for_stepping_quirk()" does its job by setting the new levels of brightness, the screen starts flashing, and the quirk ends up to be (wrongly) disabled. This happens randomly and seems to be caused by the number of levels checked; increasing this number from 2 to 3, fixes the problem.

[Fortunato Ventre (voria)]

If the module is loaded when the brightness is initially to
level 0, the function "check_for_stepping_quirk()" fails to detect that quirk
is needed. This is because at level 0 the brightness control behaves in a
different way.
Increasing the brightness level from 0 to 1 before doing the quirk test fixes
the problem.

[Felix Vollmer (felixvollmer)]

I can confirm we need a special check for 0 I just tested your patch and it is working. I can't reproduce bug mentioned in #22 (on Samsung N220), but it doesn't do anything bad, so I think it should be used.

But there must be a bug in code, because if I load the module the screen brightness changes. I couldn't see why
set_brightness(initial_level);
isn't really working.

I just got an idea for the general quirk problem. Wouldn't it be the easiest to switch first to level 0 and than to the desired level ? (I'm no expert on this and I didn't tried it but I think this should always work (if switching is fast enough))

[Felix Vollmer (felixvollmer)]

I tested my Idea and it is just working. All I changed is from original 3.0 kernel samsung-laptop.c is the "set_brightness" function. I can't notice any problems with the fast change to min_brightness. I think this should work on any Samsung Laptop and doesn't require any complicated quirk check. Sry I don't have a patch right now but this is the code I used for testing:

static void set_brightness(u8 user_brightness)
{
 if (user_brightness == read_brightness())
  return;
 u8 user_level = user_brightness + sabi_config->min_brightness;
 sabi_set_command(sabi_config->commands.set_brightness, sabi_config->min_brightness);
 sabi_set_command(sabi_config->commands.set_brightness, user_level);
}

This code might be a bad Idea or bad written. I never coded anything hardware or kernel related. Sry.

[Fortunato Ventre (voria)]

Nice idea :)
I've tested your solution on my NC10 and it works fine, and I like the simplicity of the fix.

For anyone interested to try it, I've built a package called 'samsung-laptop' which contains the patched kernel module in DKMS format, so it can easily be installed on a running kernel. It's available on my testing repository:

https://launchpad.net/~voria/+archive/archive

[Felix Vollmer (felixvollmer)]

The ppa will make testing much easier. good idea!
voria, are you in contact with Greg Kroah-Hartman? Maybe he has some background infos on Sabi (there isn't any public documentation, is it?).
I think we should also use patch mentioned in #13 because this bug is still relevant.

[Fortunato Ventre (voria)]

Sorry for the late answer.

I've updated the PPA package, it now includes all the relevant patches and uses your suggested method to change the brightness.
So far, it works good here.

I've sent an email to Greg Kroah-Hartman. I sent him a link to this bug report, and asked for his opinion on the subject.
If any news I'll let you know.

[mak ersky (makersky)]

NF310 is also affected by this bug.

[Fortunato Ventre (voria)]

I received a reply from Greg KH:

"I'm traveling at the moment, and can't see the launchpad bug, but glad
to hear that it fixes the issue for you. Hopefully someone forwards the
patch to me, in a format that I can apply it in, so that it gets added
to the main kernel tree :)"

[Matt Sturgeon (mattsturgeon)]

Samsung N110 is also effected

Timescale for getting a fix to users?

[papukaija (papukaija)]

This bug is likely to be fixed in upstream first, so please be patient. You can also use the Fortunato's PPA (ppa:voria/archive - link in comment 26) to fix this bug.

[Matt Sturgeon (mattsturgeon)]

Thanks papukaija, no impatience; just curiosity (Ok maybe abit of impatience too lol)

An intermediate solution is of course to disable "dim screen to save power" in System Settings -> Screen (I've noticed that the BacklightUp + BacklightDown trigger is also fixed by this).

I will install the PPA package on the netbook, please say if there's any specific tests or files to help test the patch :-)

[Chris Rowson (christopherrowson)]

I've marked bugs #776637 & #876775 as duplicates. A few people subscribed to those too (so the problem is probably rather widespread).

[Ketil Wendelbo Aanensen (ketilwaa-deactivatedaccount)]

Using a Samsung x125.
I first followed the instructions here: http://www.voria.org/forum/viewtopic.php?f=3&t=821&hilit=brightness+flicker
Then I instead used the Voria PPA. The flickering does not happen, but I'm unable to adjust the backlight with the Fn + arrow keys. Is this expected behaviour, a bug or did I screw up anything? If I screwed something up, please let me know.

[Ketil Wendelbo Aanensen (ketilwaa-deactivatedaccount)]

I'm sorry, just realized my foul up. I had forgotten to update Grub after reverting the changes in abovementioned Voria forums. So, now I can adjust the backlight, but it does not automatically change when (un)plugging power chord.
Sorry to distract anyone.

[Matt Sturgeon (mattsturgeon)]

I've now managed to upgrade my sister's N110 to Oneric thanks to the DKMS module fix, appears to be working 100% correctly, but I may be missing something ofcourse

@Ketilwaa are you sure that your settings are not to fault here? I don't think that's related to this bug :)

[Felix Vollmer (felixvollmer)]

Is this really a regression? Before 2.6.39 There was no backlight changing. Since 2.6.39 the samsung-laptop module is activated by default and we have a backlight changing problem.

ketilwaa: I also think that your problem is not related to this bug report

[papukaija (papukaija)]

I consider this as a regression since the brightness/backlight control worked perfectly (for the exception of togling the screen on/off but that's bug 296489) on NC10 in Natty witout flickering.

[Matt Sturgeon (mattsturgeon)]

I also consider this a regression (N110) from natty, the error that interrupts workflow was not present in natty.

[Vladimir Janowski (waldemar.yan)]

I have the Samsung n127 (the system has identified it as the n128), and I found a workaround:
You must remove the module samsung-laptop in /etc/rc.local:
rmmod samsung-laptop
And restart OS, but brightness/backlight will not work, so you must log out and again log in... And it all worked!
P.S. Will it work for you? And how to automate this process? I do not know...

[Felix Vollmer (felixvollmer)]

waldemar.yan: I'm pretty sure that something is wrong with your workaround. This shouldn't work. By unloading the samsung-laptop module you can't change the backlight without direct hw access. You must have loaded some (other none default?) module for this. Please post your lsmod output.

For a real workaround use vorias ppa #26. It contains a real fix, that still isn't in kernel.

btw: you can blacklist a module, instead of unloading it on boot...

[Vladimir Janowski (waldemar.yan)]

There are my lsmod outputs:
After unloading the samsung-laptop (backlight doesn't work): lsmod 1.txt
And after logout and login (backlight work): lsmod 2.txt

[Tauno Tammemäe (tauno-t)]

I have Samsung NP-R530 laptop computer, did a clean install of Ubuntu "Oneiric Ocelot" a.k.a Ubuntu 11.10 and had the same issue until I added " acpi_backlight=vendor" to the kernel parameters. After doing that i ran the command "sudo update-grub" and rebooted my machine. Everything seems to be working normally now, no flickering and i can change backlight brightness with "FN + arrow keys (function keys to change backlight brightness) while running my computer on battery.
1) Type "sudo nano /etc/default/grub" (replace nano with your favourite text editor, if needed, e.g gedit)
2) Add "acpi_backlight=vendor" to the GRUB_CMDLINE_LINUX_DEFAULT parameters, so that...
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
...or something similar becomes...
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"
3) Close nano (CTRL+X) and save changes (Y) or save changes and close if using another kind of editor.
4) Type "sudo update-grub" to terminal
5) Type "sudo reboot" , after that your problem should be gone.
Glad to share my experience and possibly help some other Ubuntu users.

[neferty (roman-semko)]

Thanks for you input tauno. However this didn't do it on Samsung n130 :-/

[papukaija (papukaija)]

Could someone please sent the final patches to Greg KH? Thanks in advance.

[Moriz (m.h.a)]

@neferty:
On my Samsung N130 Tauno's suggestion didn't either, but the samsung-backlight package from https://launchpad.net/~voria/+archive/ppa as described in comment #26 (see also my description in Bug #784523)

[polarapfel (tobias-weisserth-eu)]

I am really looking forward to a fix. The Samsung N130 netbook is not really useable right now.

[Felix Vollmer (felixvollmer)]

@polarapfel use the ppa until kernel fix
@all
We should send Greg Kroah-Hartman the patch from #25 (this one is used in the ppa) as a patch against the vanilla kernel. He is the maintainer. I'm at the moment too busy.

[Johann Bach (johann-bach-deactivatedaccount)]

FYI ...

Quite a few issues in samsung-laptop were fixed in the version going into the 3.2 kernel:

http://git.kernel.org/?p=linux/kernel/git/stable/linux-stable.git;a=blob_plain;f=drivers/platform/x86/samsung-laptop.c;hb=HEAD

Ubuntu 12.04 will be using the 3.2 kernel.

Recently Corentin Chary volunteered to take over the maintenance of the samsung-laptop platform driver from Greg KH (see https://lkml.org/lkml/2011/11/22/544). Corentin made quite a few enhancements and provided a git repo with his changes:

https://github.com/iksaif/samsung-laptop-dkms

If you prefer patches, they were posted on https://lkml.org/lkml/2011/11/26/ (PATCH v2 10/16 was updated and reposted on 2011/11/28).

I think the plan is to get Corentin's samsung-laptop changes into the 3.3 kernel.

[Seth Forshee (sforshee)]

FlexxxV: The fix for the min/max brightness calculations has been applied to oneiric via stable updates. I've got a test build I did for the NF310 that adds the brightness quirk patch; would you mind verifying that it fixes the issue on your machine? Thanks!

  http://people.canonical.com/~sforshee/lp897378/linux-3.0.0-14.23~lp897378v201112012054/

[Felix Vollmer (felixvollmer)]

sforshee: It works for me as expected. I hope the patch will be soon in the oneiric-update repo. :D

[Felix Vollmer (felixvollmer)]

sforshee: There is the problem. Take a look at #23. The patch should patch this problem.

Other possibility is to use my solution from #25 instead of brightness quirk and #23 patch. This patch is also in vorias ppa.

[Seth Forshee (sforshee)]

I pulled in the upstream version of the patch from comment #23 and did another test build. Please let me know if it fixes the problem, and if it does I'll work on getting both patches applied to oneiric. Thanks!

  http://people.canonical.com/~sforshee/lp810093/linux-3.0.0-14.23~lp810093v201112021425/

[Felix Vollmer (felixvollmer)]

I have a good news and a bad news.
Good news:
Backlight changing is for me now working as expected.
Bad News:
Loading the kernel module is changing the backlight when it is loaded

I think the problem is somewhere in the quirk detection. I tried to find it some time ago and came up with the solution from #25.

I just created this patch for the backlight module. The patch is against current ubuntu oneiric linux source and includes min max corrections. With this patch it isn't necessary to detect the quirk, because we are using the special behaviour of the backlight controller on minimum.

[Seth Forshee (sforshee)]

Most of the changes in the patch you attached are already applied to oneiric (although not yet released). We're going to want to take the versions that are in mainline Linux instead of that one for several reasons -- first, it makes backporting future upstream bug fixes simpler; second, the upstream version is likely to have wider testing; and third, it keeps things consistent with how future versions of Ubuntu will behave (since we'll get the upstream fixes by default when we move forward kernel versions).

The difference between yours and the upstream fix is essentially that yours avoids the quirk detection by applying the quirk to all machines. This changes the way things are done for machines that already work, and while it seems like it shouldn't cause problems on those machines it does introduce some risk of regression. For stable updates minimizing the risk of regression is key, so that's another reason to use the upstream fix.

It sounds like the two patches do fix your backlight issues, even if there is the annoyance of changing the backlight level when the module is loaded. I'll work on getting them applied for a future oneiric update. Thanks!

[Seth Forshee (sforshee)]

Adding oneiric nomination, and setting the main task to Fix Released since these fixes are already present in Precise.

[Felix Vollmer (felixvollmer)]

sforshee:
ok thx. Good to see a really annoying bug from 2.6.39 being fixed.
If I have some spare time, I might take another look at the module loading problem.

[papukaija (papukaija)]

The linux v.3.0.0-14.23 is now in -proposed and its changelog includes "* platform: samsung_laptop: fix samsung brightness min/max calculations"! The proposed kernel is tracked in bug 893213.

[papukaija (papukaija)]

@Seth: I installed linux v.3.0.0-14.23 from -updates and the flickering went away but I can only set the brightness to 0%, 10% (estimated) and 100% on my Samsung NC10. Should this bug be reopened or should I open a new bug?

[Felix Vollmer (felixvollmer)]

papukaija:
The patch isn't included in v.3.0.0-14.23. I think best is to wait for 3.0.0-15. You could use the kernel from #55 until new update.

[Herton R. Krzesinski (herton)]

This bug is awaiting verification that the kernel for Oneiric in -proposed solves the problem (3.0.0-15.24). Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-oneiric' to 'verification-done-oneiric'.

If verification is not done by one week from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Felix Vollmer (felixvollmer)]

Hey,
I just installed the new kernel and backlight is working as expected. I just changed the tags...

[ImMortallity (martin-pleister)]

Cool story.
Stopped reading halfway through because it starts about having to recompile packages and more of that stuff.
I'm not very tech savvy when it comes to Ubuntu and am not interested in reading through 64 comments to find out whether or not someone has posted proper instructions on how to fix the problem.
Now, how do I update this samsung-laptop file so that it doesn't flicker anymore? Preferably with clear instructions on how recompiling packages works and how it affects my usage of Aptitude Package Manager (will it say my package needs updating, since it's different from the version Apt has in its repository?).
Thanks in advance!

[Felix Vollmer (felixvollmer)]

@ImMortallity
the update is in Oneiric proposed.

So 3 steps are needed right now:
*activate the proposed repo
*Install new kernel
*deactivate the proposed repo

Or wait until the patched kernel is in the official updates repo.

[papukaija (papukaija)]

I'm using the the kernel from -proposed and I'm having flickering issues on nearly every boot on my Samsung NC10. Could you please help me to debug this issue?

[Felix Vollmer (felixvollmer)]

papukaija: please post your dmesg output and lsmod output.

[papukaija (papukaija)]

Thanks for the help. I've also attached the full log files.

dmesg | grep samsung: [ 19.877753] samsung_laptop: found laptop model 'NC10'
lsmod | grep samsung: samsung_laptop 13353 0

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux - 3.0.0-15.25

---------------
linux (3.0.0-15.25) oneiric-proposed; urgency=low

  [Brad Figg]

  * Release Tracking Bug
    - LP: #910894

  [ Upstream Kernel Changes ]

  * Revert "clockevents: Set noop handler in clockevents_exchange_device()"
    - LP: #904569

linux (3.0.0-15.24) oneiric-proposed; urgency=low

  [Herton R. Krzesinski]

  * Release Tracking Bug
    - LP: #903188

  [ Alex Bligh ]

  * (config) Change Xen paravirt drivers to be built-in
    - LP: #886521

  [ Chase Douglas ]

  * Revert "SAUCE: HID: hid-ntrig: add support for 1b96:0006 model"
    - LP: #724831
  * Revert "SAUCE: hid: ntrig: Remove unused device ids"
    - LP: #724831

  [ Seth Forshee ]

  * SAUCE: dell-wmi: Demote unknown WMI event message to pr_debug
    - LP: #581312

  [ Upstream Kernel Changes ]

  * Revert "leds: save the delay values after a successful call to
    blink_set()"
    - LP: #893741
  * xfs: Fix possible memory corruption in xfs_readlink, CVE-2011-4077
    - LP: #887298
    - CVE-2011-4077
  * drm/i915: fix IVB cursor support
    - LP: #893222
  * drm/i915: always set FDI composite sync bit
    - LP: #893222
  * jbd/jbd2: validate sb->s_first in journal_get_superblock()
    - LP: #893148
    - CVE-2011-4132
  * ALSA: hda - Don't add elements of other codecs to vmaster slave
    - LP: #893741
  * virtio-pci: fix use after free
    - LP: #893741
  * ASoC: Don't use wm8994->control_data in wm8994_readable_register()
    - LP: #893741
  * sh: Fix cached/uncaced address calculation in 29bit mode
    - LP: #893741
  * drm/i915: Fix object refcount leak on mmappable size limit error path.
    - LP: #893741
  * drm/nouveau: initialize chan->fence.lock before use
    - LP: #893741
  * drm/radeon/kms: make an aux failure debug only
    - LP: #893741
  * ALSA: usb-audio - Check the dB-range validity in the later read, too
    - LP: #893741
  * ALSA: usb-audio - Fix the missing volume quirks at delayed init
    - LP: #893741
  * KEYS: Fix a NULL pointer deref in the user-defined key type
    - LP: #893741
  * hfs: add sanity check for file name length
    - LP: #893741
  * drm/radeon: add some missing FireMV pci ids
    - LP: #893741
  * sfi: table irq 0xFF means 'no interrupt'
    - LP: #893741
  * x86, mrst: use a temporary variable for SFI irq
    - LP: #893741
  * b43: refuse to load unsupported firmware
    - LP: #893741
  * md/raid5: abort any pending parity operations when array fails.
    - LP: #893741
  * mfd: Fix twl4030 dependencies for audio codec
    - LP: #893741
  * xen:pvhvm: enable PVHVM VCPU placement when using more than 32 CPUs.
    - LP: #893741
  * xen-gntalloc: integer overflow in gntalloc_ioctl_alloc()
    - LP: #893741
  * xen-gntalloc: signedness bug in add_grefs()
    - LP: #893741
  * powerpc/ps3: Fix lost SMP IPIs
    - LP: #893741
  * powerpc: Copy down exception vectors after feature fixups
    - LP: #893741
  * backing-dev: ensure wakeup_timer is deleted
    - LP: #893741
  * block: Always check length of all iov entries in blk_rq_map_user_iov()
    - LP: #893741
  * Linux 3.0.10
    - LP: #893741
  * drm/i915: add multi-threaded forcewake support
    - LP: #891270
  * (pre-sta...

[papukaija (papukaija)]

Why was the fix released as this bug has failed verification status?

[papukaija (papukaija)]

Well, I guess i'll open an new bug. At least Voria's patch/PPPa is working.

[Seth Forshee (sforshee)]

papukaija: The bug is fixed for the original reporter, therefore _this_ bug is fixed. Your machine must require a different fix, and thus filing a new bug is the correct course of action.

[papukaija (papukaija)]

The NC10 story continues at bug 919773.