Thanks Robert, we'll make these tests and let you know ! Cheers,
On Tue, Apr 20, 2010 at 4:21 PM, Robert Osfield <[email protected]>wrote: > 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 > -- Serge Lages http://www.tharsis-software.com
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