[Bug 1174495] Re: kwin instability with r600 radeon and high monitor resolutions

[Harald Sitter]

** Description changed:

+ [Impact]
+ KWin 4.10.2 is using MSAA visuals with 13.04's mesa. This is unintended and leads to resource exhaustion which eventually crashes kwin.
+ This affects all users on the r600 with sufficiently sized displays.
+ 
+ [Test Case]
+ Run Kwin on the r600, if it does not crash after a while we are happy.
+ 
+ [Regression Potential] 
+ None, the fix was done by an upstream KWin and Mesa developer plus it has been incorporated into Fedora for a while plus it was used elsewhere in KWin already but not in this specific code path.
+ 
+ [Other Info]
+ None.
+ 
+ --------------------------------------
+ 
  I think the version of kwin included in 13.04 contains a known bug as described here:
  https://bugs.kde.org/show_bug.cgi?id=315089
  https://bugs.freedesktop.org/show_bug.cgi?id=61182
  
  My understanding of the problem is as follows:
  * The Mesa radeon r600 driver recently added support for MSAA GLX visuals
  * Kwin isn't aware of MSAA properties and happens to (incorrectly) pick MSAA visuals for everything
  * These visuals occupy a large amount of memory when running at high monitor resolutions
  *  Mesa is "only" capable of mapping 256MB of visuals into CPU address space at once
  * Kwin's oversize visuals exceeds this limit, resulting in constant crashes
  
  The two radeon systems I have both crash immediately after logging in,
  when running with at a resolution of 2560x1440 and desktop effects
  enabled. After restarting kwin, a crash can be induced by performing
  actions that triggers desktop effects/animations. The resulting
  callstack is attached.
  
  ProblemType: Bug
  DistroRelease: Ubuntu 13.04
  Package: kde-window-manager 4:4.10.2-0ubuntu2
  ProcVersionSignature: Ubuntu 3.8.0-19.29-generic 3.8.8
  Uname: Linux 3.8.0-19-generic x86_64
  ApportVersion: 2.9.2-0ubuntu8
  Architecture: amd64
  Date: Mon Apr 29 19:53:57 2013
  InstallationDate: Installed on 2013-04-27 (2 days ago)
  InstallationMedia: Kubuntu 13.04 "Raring Ringtail" - Release amd64 (20130424)
  MarkForUpload: True
  SourcePackage: kde-workspace
  UpgradeStatus: No upgrade log present (probably fresh install)

-- 
You received this bug notification because you are a member of Kubuntu
Bugs, which is subscribed to kde-workspace in Ubuntu.
https://bugs.launchpad.net/bugs/1174495

Title:
  kwin instability with r600 radeon and high monitor resolutions

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/kde-workspace/+bug/1174495/+subscriptions