Laptop Monitor Brightness reduced to minimum and disabled after disconnection from external monitor.

[Alaak]

Hi,

I have the following problem under Ubuntu 14.04. As soon as I disconnect my external monitor from my Laptop (Lenovo X1 Carbon), the brigthness is reduced to minimum (backlight switches off) and I can not increase it again. When I use the brightness control keys the brightness bar shows that it is set to maximum even though it clearly is not. Using the control keys still changes the brightness bar but does nothing to the brightness itself.

Upon a restart of the laptop the brightness returns to its maximum and is controllable again.

I encountered this problem under the Unity version shipped with Ubuntu 14.04, but it might happen with other desktop managers as well.

This problem did not exist when my Laptop was running under Ubuntu 13.10.

[Ubuntu Foundations Team Bug Bot (crichton)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that your bug report is not filed about a specific source package though, rather it is just filed against Ubuntu in general. It is important that bug reports be filed about source packages so that people interested in the package can find the bugs about it. You can find some hints about determining what package your bug might be about at https://wiki.ubuntu.com/Bugs/FindRightPackage. You might also ask for help in the #ubuntu-bugs irc channel on Freenode.

To change the source package that this bug is filed about visit https://bugs.launchpad.net/ubuntu/+bug/1307877/+editstatus and add the package name in the text box next to the word Package.

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[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Dennis (deki24)]

Same here, I'd like to have a workaround that prevents me from restarting every time I unplug the monitor.

[Alaak (alaak-gmx)]

Actually the bug ceased to exist with Ubuntu 14.04 leaving beta.

[Sérgio Serra (a-sergio-serra)]

I have the same problem with ubuntu 14.04. Any workaround?

[Maxus Mica (gehibimayu)]

Same problems happens for me with Mobile Intel® GM45 Express Chipset. There is no need to restart though. Logging out brings the full brightness back. But this is very annoying for the workflow as one can guess.

[Dagal Hencik (dagezal)]

This bug seems to be related to a kernel problem. Fedora is dealing with the problem as well.

Have a look at these two bug reports:

https://bugzilla.redhat.com/show_bug.cgi?id=1067071

and

https://bugzilla.redhat.com/show_bug.cgi?id=1093991

[Mauro Miolo (mauro-miolo)]

i confirm this bug.
I cant adjust the brightness after second monitor unplug.

[Benjamin Xiao (ben-r-xiao)]

I can confirm this bug. However, the brightness control gets disabled right after I plug in a secondary monitor and remains disabled when I disconnect.

[Ryan Klarhölter (ryanklarhoelter)]

No brightness issues when I disconnect the external monitor while the notebook screen has focus (click on a window or the empty desktop on the notebook screen).

[alexeiz (alexeiz)]

#10 workaround doesn't work for me.

[Dennis (deki24)]

Seems to be fixed with 3.13.0-35 kernel update.

[Sampo Savolainen (sampo-savolainen)]

3.13.0-35 kernel update did not fix the issue for me.

[Dennis (deki24)]

For me neither, today the problem is back again.

[Victor Sergienko (singalen)]

I wonder if it has something to do with the fact that external monitor is configured primary.

[Sampo Savolainen (sampo-savolainen)]

In my case the external monitor is indeed the primary.

[Sérgio Serra (a-sergio-serra)]

Same here. After connecting external monitor brightness control keys stop working.
Althought I can change brightness "manually" on on "Brightness & Lock" settings.

I'm using nvidia open source driver .

[Dennis (deki24)]

I've not hit the bug after updating to Ubuntu 14.10 - hopefully it's fixed now.

[penalvch (penalvch)]

Alaak, this bug report is being closed due to your last comment https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1307877/comments/4 regarding this being fixed with an update. For future reference you can manage the status of your own bugs by clicking on the current status in the yellow line and then choosing a new status in the revealed drop down box. You can learn more about bug statuses at https://wiki.ubuntu.com/Bugs/Status. Thank you again for taking the time to report this bug and helping to make Ubuntu better. Please submit any future bugs you may find.