External monitor causes screen corruption

Thanks for your report.

Could you please attach the output of 'sudo lspci -v'

Thanks.

Likely dup of bug 808677

Attached.

This does not feel like a dup of that bug to me. The behaviour is different and this GFX card occasionally has screen corruption even without an external monitor.

Does it happen with Unity-2D or only Unity ?

To login on unity-2d select 'Ubuntu 2d' in the combo box on the login screen.

In Unity 2D the external monitor works without a problem. A quick test did not produce any screen corruption.

However in natty, I get occasional screen corruption even in the basic Gnome 2 environment. This usually happens with Eclipse, which can't be easily tested with the live ISO. (However I do know that upstream has improved the driver for this video card quite a lot so maybe those bugs have been fixed.)

Thanks for confirming. I'll target for oneiric.

bug 811052 was opened against Unity, which I think is the correct package. The reason for that is that gnome shell does not exhibit this bug for me (2d desktops also do not exhibit issue). Unless I'm mistaken, that means that the issue is not [entirely] with compiz.

Scott, I agree, and this looks like a regression over bug 795454 and bug 795458.
For reference, other issues related to this one:
bug 808677
bug 808685

See also discussion on IRC http://irclogs.ubuntu.com/2011/07/13/%23ubuntu-desktop.html starting at
"seb128 RAOF, hey, is there known xorg breakage on intel with dual screen? 08:57"

The conclusion is very likely a unity issue but the dev need to do more testing
"""
seb128 so unity bog it seems 09:19
smspillaz oh, monitor hotplug is awesome 09:20
smspillaz seb128: well, not conclusively 09:20
smspillaz it could just be on certain hardware that compiz gets that 09:20
seb128 well RAOF gets the issue with unity and it seems to work without unity 09:20
smspillaz seb128: I think I need to do more testing 09:20
smspillaz like, checking if I get the issue with unity :) 09:20
smspillaz since I don't usually hotplug this monitor
"""

Just for reference, as a screenshot of the issue might help others identify it, I'm re-attaching screenshot from another duplicate bug.

I was surprised, but this actually shows the issue perfectly.
Note, the browser is cut off above the Ubuntu logo, and is not viewable at all on the second monitor (first is 1440 wide, the left).

Tracking the bug also on Unity now. It may be between Compiz & Nux for example. I'd like Jay's input first, in particular as he has access to the Lab's HW to try and reproduce this more easily.

I was sable to reproduce the problem on my intel system: core i3 + GMA HD GPU + VGA cable.

Something notable is this:
- The bug can be reproduced when Unity starts without multi-monitor support. Then you plug in an external monitor and configure the system for a multi-monitor configuration.
- If Unity starts with multi-monitor config already enable, then the problem cannot be reproduce. The system works fine in multi-monitor configuration.

I have tested the system in several configurations and multi-monitor was working fine. It is only the case mentioned above that causes problem.
I have briefly tested my desktop system (ATI GPU + open source driver) but couldn't reproduce the problem. So there maybe something specific to intel here.

There is a fix for the the original problem mentioned in this bug.

Unity 4.8.2 is now in Oneiric.

fixed here for me. Thanks!

oneiric has seen the end of its life and is no longer receiving any updates. Marking the oneiric task for this ticket as "Won't Fix".