QSG_RENDER_LOOP woes

[Sebastian Kügler]

On Friday, May 09, 2014 16:03:31 Martin Gräßlin wrote:
> On Friday 09 May 2014 15:56:53 Sebastian Kügler wrote:
> >
> > Since 30d2489930 in plasma-workspace, we're setting the QSG_RENDER_LOOP to
> > "basic", if it's not specified otherwise by an env var. This has been done
> > to prevent crashes in the threaded renderer, but unfortunately, it seems
> > to
> > come with its own set of problems: Plasma produces artifacts, high CPU
> > load
> > and grinds to a complete halt after a while.
> >
> > 
> >
> > I've tried setting the QSG_RENDER_LOOP to threaded, and that does indeed
> > prevent those problems, but obviously, plasma-shell is more crashy with
> > it.
> > Now some of those crashes (at least one I've observed) is indeed in the
> > scenegraph, but I've also seen other crashes (one in groupmanager of the
> > taskbar, indirectly, not sure if that's related).
> >
> > 
> >
> > I think we might need to revisit this patch, and find a "stable" way
> > forward. Just switching to basic renderloop doesn't seem to be the
> > solution. :/
> 
> Please note that Qt itself switched it off for all of Mesa. The change now
> was  more to only have one possible way of usage and preventing us hunting
> down non-reproducable bugs.
> 
> The crashes we see with threaded render loop cannot be fixed or worked
> around  if I understand the Qt commit disabling it for all of Mesa
> correctly. Have a look at the plasma-devel archives, I sent a FYI mail some
> time back.

I remember that one. That email doesn't say much, except for your "basic works 
for me" in kwin. I didn't see any problems with kwin, only with plasma-shell, 
and I only changed it for plasma-shell in my tests: that made a difference (on 
Intel).

Cheers,
-- 
sebas

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