On Stability

KWin has been known as a rock-solid window manager in the KDE 3.5 times. I was wondering how the situation is nowadays with focus no longer on window managing but on compositing. Currently we are experiencing a major problem in combination of Intel/Mesa drivers with either fullscreen flash videos or OpenGL screensavers. Since the release of Kubuntu Natty we receive two to three new duplicates each day. In case you are experiencing this issue: do not report! Neither to us, nor to Mesa nor to (K)Ubuntu. It is a known issue and Upstream is working on a fix! As a workaround, do not use Flash to watch Youtube videos and do not use OpenGL screensavers. The issue is the most often reported bug against KWin of all time, now.

The fact that we receive duplicates for an issue clearly recognized by DrKonqui as already reported multiple times can tell us a lot about other problems. If we have a real stability issue we receive many bug reports and we have seen this in the past. Apart from the noise of mentioned crash above we have hardly received any new issue lately, so I thought about going through all our crash reports to get an overview of our current stability. I am also a KWin user and cannot remember a single KWin crash at work with openSUSE 11.4.
After todays and yesterdays triaging there are less than 20 open crash reports and I am only able to reproduce one of them and fixed another one. Most of our previously open crash reports have not seen any activity over the last year(s). Many of them had been reported against 4.4 or an even older release without duplicates of newer versions. All those have been closed, given that we most likely fixed these issue. Many thanks to Thomas for fighting crashers in various effects and the window grouping functionality. (Keeping the crash reports open does not make any sense as there have been too many code changes to make any use of old crash reports.)
The remaining open issues which I am not able to reproduce are in most cases missing a description how to reproduce, so it is very unlikely that these affect our users and it is possible that they are already fixed. Given this, I am happy to say, that also as a compositor KWin is rock-solid 🙂

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13 Replies to “On Stability”

  1. Currently we are experiencing a major problem in combination of Intel/Mesa drivers with either fullscreen flash videos or OpenGL screensavers.
    Uhm, I’m with Intel 4500HD and my KWin hadn’t crashed since…no, really don’t know since when, but it was long ago. Flash is working fine as well even on fullscreen and enabled composite.

    The only issue(but still without crashing) was with this xf86-video-intel fuckup, but just like you said setting KWIN_DIRECT_GL=1 fixed it.
    Happy to be an exception, this time 😛

  2. I’m having a few issues ( no crashes though ), but I can’t tell if it is kwin, xorg or nvidia that’s to blame. Do you want me to file bug reports and let you sort of whether or not kwin is the culprit?

    A short summary:
    System: lenovo t510 nvdia 3100m, kubuntu 11.04.
    1) When running composited I sometimes get lots of pixels around windows, as seen at http://benriach.widell.net/~andrnils/screen.mkv. I gets a bit better when compositing is disabled, but only goes away on reboot.

    2) When running composited X hangs, and I see a kworkerthread and Xorg competing for ( and running flat out ) on cpu. It seems pretty random as to when it hangs, can be anything from moving mouse pointer to switching desktop.

    3) Variation of 2) but happens both when running composited and non-composited. When watching 720p .mkv files pretty often X hangs when mplayer finishes and is just about to “remove/destroy” it’s window. I’m not using vdpau.

    I’ve tried to find anyone else with similar issues but either my search terms are bad or I’m the only one seeing those issuses.

    Keep up the great work and interesting blog posts 🙂

  3. Hello Mertin!

    It’s nice to read about stability, wherever it is, especially if it is related to Linux and/or KDE. But I’d like to go OT and ask you, have you seen the client side decoration support in Wayland thread? It’s already on Phoronix. I know you have a strong position regarding that question, but your name doesn’t seem to appear on the ML thread regarding that topic.

    Best regards,

    1. I consider such topics as way too early to discuss and don’t want to join useless bikeshedding.

    1. Stupid regression in the nvidia driver (hits at least 270.41.06) and is related to ARGB clients and has different outcomes on XRender (blocks often for 1-2 seconds) and GL (blocks sometimes for a veeeeery long time)
      run “konsole –notransparency –nofork” (the –no-fork only ensures a new process is really started even if another konsole is already up)

      the sad thing is tat ultimately libkwinnvidiahack should do nothing but prevent this issue (which has however not appeared for quite some time) but apparently the environment is ignored 🙁

  4. Off-topic, but have you seen the talk of Wayland forcing client-side decorations?

    1. yes, but I do consider such discussions on Wayland list pre-mature, I consider the Wayland list not the body to decide such things as it is out of scope for Wayland. I won’t add support for CSD – neither on X nor on Wayland. So they can discuss what they want, KDE as a major player won’t support CSD.

      1. i am just curious.. how does google chrome do it? i told chromium to “Use system title bar and borders” but without me telling it what to do it looks like client side window decorations to me? whats the trick if kde does not support this?

  5. … Or maybe we need more people to test Kwin, so we could catch more bugs! 😉
    Just joking, kudos for the good job.

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