[vlc-devel] [Issue N176472] QCleanlooksStylePrivate::lookupIconTheme is broken

[qt-bugs at trolltech.com]

On Thursday, 30. Aug 2007 14:29 Rafaël Carré wrote:

> qt-bugs at trolltech.com a écrit :
> > Hi Rafaël,
> >
> > On Wednesday, 29. Aug 2007 22:43 Rafaël Carré wrote:
> >> qt-bugs at trolltech.com a écrit :
> >>> Hi Rafaël ,
> >>>
> >>> Are you able to send us a stack trace at the point where you
> >>> application locks/hangs?
> > > i give you a strace log:
> > > http://people.videolan.org/~funman/trolltech/strace.log
> > >
> > > there is 2 select() call that give a Timeout (search for "Timeout"
> > > in the log, they're espaced of 6 lines).
> > >
> > > the first timeout almost immediately, and the second is the one
> > > that makes the application hang. you'll also note they're 10-20
> > > lines after clone() calls (used to exec gconftool-2)
> >
> > Thank you for providing me all these details, certainly very
> > helpful. Are you able to run the following command from your shell?;
> >
> > gconftool-2 --get /desktop/gnome/interface/icon_theme
> >
> > Does it give any results. Qt uses gconftool to pick up the icon
> > themes and we do that in a QProcess in a thread and if gconftool
> > does not repsond back then it will timeout and the process will
> > probably die.
>
> % time gconftool-2 --get /desktop/gnome/interface/icon_theme Human
> gconftool-2 --get /desktop/gnome/interface/icon_theme 0,01s user 0,00s
> system 76% cpu 0,016 total
>
> sorry for not being explicit, there is no problem using gconftool-2, I
> think the problem is that the QProcess terminates too quickly, and
> because of that there is a timeout in QT code.
>
> as you can see, gconftool-2 works well and outputs the desired
> information very quickly.
>
> >
> > I have reported this issue to the developers. This doesn't seem to a
> > known problem and doesn't seem to be reproducible here. However,
> > they will investigate further on this problem.
> >
>
> did you try the little vlc build i made for you ? maybe you're not
> allowed to execute untrusted code, i would understand of course.
>
> i suppose it happens with vlc and not with a simple sample because vlc
> adds an overhead, and delays qt4 execution, i suppose the bug is a
> race condition.
>
> i CC'ed our conversation to the VLC developers mailing list as they
> are too intersted in this issue.
>
> > > > Can you reproduce the problem with a small example, can you
> > > > please send us such example?
> > > Unfortunately, i've been unable to narrow it to a small example :(
> > > Here is the diff i applied to the trunk version of vlc (subversion
> > > repository): http://people.videolan.org/~funman/trolltech/qt4.diff
> > >
> > > > Which Desktop Manager are you using, Gnome?
> > > Yes, gnome 2.19.91
> >
> > This release is not stable and therefore not supported by Qt.
> > Basically,
> > it is not guaranteed that it will work. Have you tried a stable
> > Gnome
> > release, like 2.18 or older? Do you see any problems on other
> > Desktop
> > Managers, like KDE, BlackBox, XFCE?
>
> I see the same problem using gnome 2.18, and Xfce 4.4.0.
>
> Note the bug is specific to cleanlooks style, and this style is mostly
> used with a gnome desktop, so the utilisation of a gnome-specific tool
> to get icon theme info.
> More over, the running desktop will not influence the invocation of
> gconftool-2
>
> >
> > > > Unfortunately, I am not able to reproduce the problem here when
> > > > I use the Cleanlooks style after I set it up in the qtconfig
> > > > tool. I would also recommend to get the latest Qt4.3.2 snapshot
> > > > or the latest Qt 4.3.1 stable release and try to compile/install
> > > > it manually in your system to see whether that makes any
> > > > difference at all.
> > > Setting up .deb qt4 packages is a pain and very long :( so i won't
> > > do it if not necessary.
> > >
> > > To see if you can reproduce the problem without the pain of
> > > building vlc, i uploaded a minimal package on:
> > > http://people.videolan.org/~funman/trolltech/vlc.tar.gz
> > >
> > > run as: LD_PRELOAD=lib/libvlc.so ./bin/vlc --plugin-path lib -I
> > > qt4
> > >
> > > thanks for your reply, let me know if that helps you to reproduce
> > > the problem.
> >
> > I will try to reproduce the problem here as well on my machine.
> > However, as I mentioned previously the Gnome version you are using
> > is not a stable one and therefore it is not supported since it could
> > a problem on Gnome's side.
>
> seeing that gconftool-2 works perfectly i suspect it's not the case :/


Hi Rafaël,

Thank you for all the detailed info you have provided me with. This
seems like a bug to me and therefore I have created a task for the
QCleanLooksStyle developer to investigate further on this issue.
I have forwarded all the information to the developer and he should be
able to get the minimal VLC code that you sent me to try to reproduce
and debug the problem.
You can track this issue on the task tracker with ID: 177063

Thanks for your cooperation and all the given feedback.
Hopefully this issue will be resolved asap.

Kind regards,
Petref

--
Petref Saraci
Support Engineer
Trolltech ASA, Oslo - http://www.trolltech.com
======================================================================
Qtopia Greenphone Developer Challenge,
Show off your talent, your creativity, your Linux technology savvy.
Register now: http://www.trolltech.com/developer/tt/gpdevchallenge
======================================================================