VMD-L Mailing List

From: John Stone (johns_at_ks.uiuc.edu)
Date: Thu Jan 21 2016 - 09:56:36 CST

Hi,
  Interesting, as you say, the post on the NVIDIA forum does indicate that the
composite extension is supported, but the NVIDIA driver README for the
latest driver version 361.18 (URL in my previous email) still says that
it is not supported. The note on the NVIDIA forum does say that it only
works if the composite manager supports quad-buffered GLX.

Looking at the bug report logs, it would seem that the "in-progress"
support for KDE and GNOME is currently stalled.
The last post on the KDE bug was in December 2014, and the poster provided
an untested KDE source code patch, for which there appears to have been
no further followup. The last post on the GNOME bug was in July 2014, and
it too got no further followup after an untested patch was posted.

Digging further, I find that googling "_META_ENABLE_STEREO", which was
one of the items added to the source code patch for the "mutter" manager
that is used by both KDE and GNOME shows that it was actually committed
to a works-in-progress GIT repo back in 2014, but that is the only place
google turns up the code. This makes me think that the patch is currently
still sitting in limbo and has not made it any further than the
work-in-progress branch of the "mutter" composite manager (which I knew
nothing about prior to today). I might be wrong, but it isn't very
encouraging looking from what I've seen so far.

It is possible that in the short-term, the best option is to drop both
GNOME and KDE in favor of a "classic" window manager that does not require
window compositing (and thus does not interfere with stereo).

Cheers,
  John Stone
  vmd_at_ks.uiuc.edu

On Thu, Jan 21, 2016 at 10:02:49AM +0100, Vlad Cojocaru wrote:
> Actually according to some info I found, the newer NVIDIA driver should
> actually provide support for Quad Buffered Stereo and Composite together
> .. Apparently, the problem may actually be with the Desktops (Compositor)
>
> Some reads about this (it may be a topic that will come more often as
> people switch to newer desktops
> ..
> https://github.com/chjj/compton/issues/270
> https://devtalk.nvidia.com/default/topic/795180/proplems-with-stereo-unde-k4200-in-linux/
> https://bugs.kde.org/show_bug.cgi?id=335859
>
> Best
> Vlad
>
>
> On 01/20/2016 11:00 PM, John Stone wrote:
> >Hi,
> > The use of stereo when the composite extension is on is prohibited
> >by the underlying video driver, VMD is just reporting what the driver says
> >when VMD asks for stereo.... The driver limitation (that the composite
> >extension ends up disabling stereo) is documented in the NVIDIA driver
> >READMEs, and the latest drivers provide a simple command line flag for
> >nvidia-xconfig to disable or enable the composite extension:
> > http://http.download.nvidia.com/XFree86/Linux-x86/361.18/README/xcompositeextension.html
> >
> >Here is the key text from the NVIDIA README:
> > "Workstation overlays, stereo visuals, and the unified back buffer (UBB)
> > are incompatible with Composite. These features will be automatically
> > disabled when Composite is detected."
> >
> >When you start the X11 server, you'll see warning messages
> >about stereo being disabled in the X11 server logs, in /var/log/Xorg.0.log
> >
> >As far as I know there is no way around this. I'm not sure why KDE
> >cannot be run without the composite extension, but if you care about
> >using stereoscopic display modes, it might be time to switch from KDE to a
> >different desktop manager.
> >
> >Cheers,
> > John Stone
> > vmd_at_ks.uiuc.edu
> >
> >
> >On Wed, Jan 20, 2016 at 06:45:30PM +0100, Vlad Cojocaru wrote:
> >>Dear VMD users, developers,
> >>
> >>I have installed the new openSUSE (Leap - 42.1) and I am able to run
> >>neither KDE nor GNOME properly with "Composite" disabled. With
> >>"Composite" enabled I am not able to use stereoscopic viewing in VMD
> >>with NVIDIA 3D vision. Does anyone know if there is any way to make VMD
> >>display stereo with the "Composite" extension enabled ? On my previous
> >>openSUSE 13.2, KDE was running properly with "Composite" disabled, so I
> >>was able to use stereo (Quad Buffered)
> >>
> >>I have the following setup:
> >>x86_64 arch
> >>VMD 1.9.2 (compiled from source)
> >>NVIDIA driver 358.16
> >>CUDA 7.5.18
> >>OPTIX 3.9.0
> >>NVIDIA 3D Vision
> >>Graphics card: Quadro K4000
> >>
> >>Thanks for any advice
> >>
> >>Best wishes
> >>Vlad
> >>
> >>--
> >>Dr. Vlad Cojocaru
> >>Computational Structural Biology Laboratory
> >>Department of Cell and Developmental Biology
> >>Max Planck Institute for Molecular Biomedicine
> >>Röntgenstrasse 20, 48149 Münster, Germany
> >>Tel: +49-251-70365-324; Fax: +49-251-70365-399
> >>Email: vlad.cojocaru[at]mpi-muenster.mpg.de
> >>http://www.mpi-muenster.mpg.de/43241/cojocaru
>
> --
> Dr. Vlad Cojocaru
> Computational Structural Biology Laboratory
> Department of Cell and Developmental Biology
> Max Planck Institute for Molecular Biomedicine
> Röntgenstrasse 20, 48149 Münster, Germany
> Tel: +49-251-70365-324; Fax: +49-251-70365-399
> Email: vlad.cojocaru[at]mpi-muenster.mpg.de
> http://www.mpi-muenster.mpg.de/43241/cojocaru 

-- 
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Beckman Institute for Advanced Science and Technology
University of Illinois, 405 N. Mathews Ave, Urbana, IL 61801
http://www.ks.uiuc.edu/~johns/           Phone: 217-244-3349
http://www.ks.uiuc.edu/Research/vmd/