Hi Serge, This does sound like a driver issue, and it's been a while since I had two NVidia cards plugged into my Linux box, but I don't recall having problems with vsync. I did, however, enable vync via the old env var:
export __GL_SYNC_TO_VBLANK=1 There is slim chance that this might work... you never know with closed driver what the logic is. Another thing you might try is to create two graphics context, one for each card and then use twinview to have a single context across both screens. On the OSG side you can create two contexts and just have two cameras per context, using different viewports to select the appropriate part of the view. You may even be able to just use a single camera across both screens if your displays are abutted vertical/horizontal in the form of a powerwall. If you can use a single graphics context per card then you'll get better performance, and if you can use a single camera per card then you'll get the best performance out the system. Whether twinview will solve the vblank issue I can't say. There is chance that NVidia reserve this for the Quadro's that have support for genlock and swap ready. Robert. On Tue, Apr 20, 2010 at 2:44 PM, Serge Lages <[email protected]> wrote: > Hi all, > I'm currently having a problem with NVidia hardware on Linux, it's not > directly OSG related, but I hope someone here can help me. > > Here is my setup : > > Ubuntu 9.10 > 195.36.15 NVidia drivers > 2 GTX 285 graphic cards (one DVI, one VGA and one HDMI port) > 4 screens (2 screens on each cards), all independents (no twinview) > Compiz disabled > On this setup, I have an OSG application running full-screen on all 4 > screens (a CompositeViewer with 4 views). My app is running at 60fps when > VSync is on, it's the screens refresh rate. > When I enable "Sync to VBlank" in the Nvidia-settings, here is the current > result : > - On the first screen of each cards (plugged on the DVI port), the VSync is > perfect, no tearing. > - On the second screen of each cards (plugged on the VGA port), tearing is > noticeable on the upper part of the screens (I have a line about 100 pixel > far from the top of the screens). > => Result : 2 screens without tearing, 2 screens with tearing in a specific > location. It seems VSync is not really performed on the second screen of > each cards. > I have also tested on GTX285 cards with 2 DVI ports with the same result. > Another note : the 4 screens are the same, all plugged in VGA with the same > resolution (using an adaptor when plugged in the card DVI ports). I've > tested with other screens with the same result. > Anyone knows where this problem comes from ? And any idea how to solve it ? > Is it a bug in recent drivers, maybe I should test olders ? > Thanks in advance for your help. > Best regards, > -- > Serge Lages > http://www.tharsis-software.com > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
