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Thread: VNC serves only black window - "QXcbIntegration: Cannot create platform OpenGL context, neither GLX"

  1. #1

    Default VNC serves only black window - "QXcbIntegration: Cannot create platform OpenGL context, neither GLX"

    Hy!

    Have a machine with an old NVIDIA NVS 290 with NVIDIA 340 driver installed from repo (to make Kaffeine + SAT DVB-S2 work).

    I tried to start vncservers, both from command line (vncserver :1) as well as from YaST.

    In both occasions the vncserver can be accessed from the LAN, but only a black window is served. :-(

    In startup logs for both these vncservers I see:

    Code:
    QXcbIntegration: Cannot create platform OpenGL context, neither GLX nor EGL are enabled
    and sometimes I see in the black VNCserver windows a message saying something with OpenGL not running, disappears really quick.

    I looked the interweb, but found nothing that would fix my problem.

    PS: Yesterday I did zypper dup (not zypper up) on the 42.3 (....tooooo much TW installs.....), hope that doesn't cause any problems?
    Kind regards

    raspu

  2. #2
    Join Date
    Oct 2008
    Location
    Glasgow, Scotland
    Posts
    1,277

    Default Re: VNC serves only black window - "QXcbIntegration: Cannot create platform OpenGL context, neither

    Warning: I have not used this for years, and it may completely be out of date.

    VNC is configured by default to use IPv4
    Linuxes are configured by default to use IPv6 and IPv4
    Many LANs are still configured IPv4 only

    This can result in an IPv4 VNC listening for an IPv6 X server (blank VNC screen).
    The quick solution was to comment out the IPv6 localhost entry in /etc/hosts on the server:--
    Code:
     # special IPv6 addresses
     # ::1             localhost ipv6-localhost ipv6-loopback
    --
    slàinte mhath,
    rayH

    ~ knowing the right answer is easier than knowing the right question.

  3. #3
    Join Date
    Sep 2012
    Posts
    7,085

    Default Re: VNC serves only black window - "QXcbIntegration: Cannot create platform OpenGL context, neither

    Quote Originally Posted by suse_rasputin View Post
    NVIDIA 340 driver installed ...
    Code:
    QXcbIntegration: Cannot create platform OpenGL context, neither GLX nor EGL are enabled
    nVidia drivers replace default openGL implementation (both for server and client) so any application that requires openGL will fail in this case. Your choices are

    1. Use DE that does not require openGL
    2. Run Xvnc making sure it picks native libglx instead of nVidia. That is basically reverse of what Bumblebee does, you can look in their script for inspiration. You will also need to make sure clients pick the right libraries - either by exporting suitable LD_LIBRARY_PATH (see mentioned script) or by using libglvnd - unfortunately not on Leap 42.x.

  4. #4

    Default Re: VNC serves only black window - "QXcbIntegration: Cannot create platform OpenGL context, neither

    Hy again!

    @eng-in: Many thanks, but all machines set to "Ignore" IPv6, whatever that means... ;-)

    @arvidjaar: Many thanks, very interesting to know! (I love this forum, although the forum doesn't love me ) )

    I uninstalled NVIDIA driver, now the VNCserver started from CLI works flawlessly! And amazingly my DVB-S2 card also!

    What doesn't work:

    - The VNCserver started via Yast: While activating after clicking "OK" the menu reaches the point "Restarting services" and the GUI (on the machine, not VNC) dies and I end up on a CLI login (reproducibly).

    - When I start a stream in VNC or Kaffeine the pic is totally black (not via VNC! Only when logged in physically!), but if I start another app like Libreoffice or Bleachbit, the stream in VNC or Kaffeine will suddenly start!

    - All windows in the GUI lack scrolling bars, nothing to see, although they work when moved with the mouse...

    Very funny! :-)

    But both VNCserver and DVB-S2 work now. You can't always get what you want... ;-)

    anazazi
    Kind regards

    raspu

  5. #5
    Join Date
    Nov 2013
    Location
    Kamloops, BC, Canada
    Posts
    4,029

    Default Re: VNC serves only black window - "QXcbIntegration: Cannot create platform OpenGL context, neither

    Quote Originally Posted by suse_rasputin View Post
    The VNCserver started via Yast: While activating after clicking "OK" the menu reaches the point "Restarting services" and the GUI (on the machine, not VNC) dies and I end up on a CLI login (reproducibly).
    Although you did not mention it in this thread, you are running KDE/Plasma on that machine using SDDM as the display manager. Switch the display manager (perhaps install kdm from the repos and switch to that, or use lightDM).

    - When I start a stream in VNC or Kaffeine the pic is totally black (not via VNC! Only when logged in physically!), but if I start another app like Libreoffice or Bleachbit, the stream in VNC or Kaffeine will suddenly start!

    - All windows in the GUI lack scrolling bars, nothing to see, although they work when moved with the mouse...

    Very funny! :-)
    If you want things smoother, perhaps try a different desktop on the remote machine: I find Xfce works great with VNC.
    "Take a Walk on a Sunny Day, Greet everyone along the way, and Make Somebody Smile, Today"
    Gerry Jack Macks"Walk On A Sunny Day" GerryJackMacks.net

  6. #6

    Default Re: VNC serves only black window - "QXcbIntegration: Cannot create platform OpenGL context, neither

    Hi!

    Yepp, normal/standard KDE/Plasma and display manager. Have one remote machine with XFCE, quite nice, but I'm more used to KDE stuff at the moment.

    And the concept of a "display manager" is slightly over my linux pay grade ;-)

    99% working for the moment, rest let's see...
    Kind regards

    raspu

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