[solved] two GTX780 in sli, three monitors, no 3D acceleration

Under linux mint debian edition, with two GTX780 in sli, and three monitors (two on the first card, one on the second, like under windows in surroung gaming mode).

I’m using the driver 331.20

I’ve tried different setups (all monitors on the first card, sli mosaic, twinview, xinerama, …) and for every setup, I’ve no 3D acceleration, except when I activate only one monitor and sli.

But I haven’t found any setup to have three monitors working with 3D acceleration under linux with my two cards in SLI.

All is running well under windows 8.1 on the same box.

I don’t know how to setup my system to have some 3D accellaration on my three monitors.

Thanks a lot,

Nicolas.

Hey nse, I currently have a GTX590, and it doesn’t let me do twinview in the nvidia control panel for more than two monitors. (Apparently it has two GPUs in it, and the twinview can’t span across multiple GPUs)

But you’re able to set up twinview for all 3 monitors? That’s great, because I just ordered a new GTX780 and I’m hoping that it solves my twinview problem.

You could activate up to four monitors on one GTX780, but without 3D acceleration, or in a way I don’t know. with the two cards, I think I could connect up to 8 monitors, but haven’t tested, due to a lack of monitors :)

I was having two GTX560Ti before, and have replaced them because I’ve read that having monitors connected to two cards disable the 3D acceleration in linux. I can now say that I’m unable to have 3D acceleration even when the 3 monitors are connected to the same card.

reading this
ftp://download.nvidia.com/XFree86/Linux-x86/256.35/README/sli.html
makes me hoping a solution but I haven’t found one.

reading this :
http://ubuntuforums.org/showthread.php?t=1703524
makes me feel you will have no luck with three monitors.

I’m ready to test some solutions, but I’ve no idea on how to solve this 3D accel problem.

4 Monitors connected to one gtx780 should work fine with 3D acceleration. Did you try to enable the Mosaic Mode with both gtx780? ( see ftp://download.nvidia.com/XFree86/Linux-x86/331.20/README/sli.html and Option “SLI” “Mosaic”).

And please read https://devtalk.nvidia.com/default/topic/522835/linux/if-you-have-a-problem-please-read-this-first/ so we’ll get some log and configuration files :)

OK, here is the config:

cat /etc/X11/xorg.conf
# nvidia-settings: X configuration file generated by nvidia-settings
# nvidia-settings:  version 331.20  (buildmeister@swio-display-x86-rhel47-05)  Wed Oct 30 18:20:32 PDT 2013

Section "ServerLayout"
    Identifier     "Layout0"
    Screen      0  "Screen0" 0 0
    InputDevice    "Keyboard0" "CoreKeyboard"
    InputDevice    "Mouse0" "CorePointer"
    Option         "Xinerama" "0"
EndSection

Section "Files"
EndSection

Section "InputDevice"
    # generated from default
    Identifier     "Mouse0"
    Driver         "mouse"
    Option         "Protocol" "auto"
    Option         "Device" "/dev/psaux"
    Option         "Emulate3Buttons" "no"
    Option         "ZAxisMapping" "4 5"
EndSection

Section "InputDevice"
    # generated from default
    Identifier     "Keyboard0"
    Driver         "kbd"
EndSection

Section "Monitor"
    # HorizSync source: edid, VertRefresh source: edid
    Identifier     "Monitor0"
    VendorName     "Unknown"
    ModelName      "Idek Iiyama PL2710HD"
    HorizSync       30.0 - 83.0
    VertRefresh     55.0 - 76.0
    Option         "DPMS"
EndSection

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BoardName      "GeForce GTX 780"
    BusID          "PCI:1:0:0"
EndSection

Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "Monitor0"
    DefaultDepth    24
    Option         "Stereo" "0"
    Option         "nvidiaXineramaInfoOrder" "DFP-3"
    Option         "metamodes" "DVI-I-1: 1920x1080 +0+0, HDMI-0: 1920x1080 +3840+0, DVI-D-0: 1920x1080 +1920+0"
    Option         "SLI" "Off"
    Option         "MultiGPU" "Off"
    Option         "BaseMosaic" "off"
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection
Section "DRI"
    Mode 0666
EndSection

A strange think is that direct rendering is reported as yes when runned as root and reported as no when runned as a user.

previous config have been generated by :
nvidia-xconfig --sli=Mosaic --metamodes=“GPU-0.DFP-0: 1920x1080+0+0, GPU-0.DFP-3: 1920x1080+1920+0, GPU-0.DFP-1: 1920x1080+3840+0”

and then nvidia-settings

you should notice that sli is setted to “Off” by nvidia-settings ???

That means you have no access to /dev/nvidia* as a normal user.

Thanks for the help. Maybe you should change the doc because all monitors has to be connected to the same card in this case.

If you are going to use fewer monitors than there are connectors, connect one monitor to each GPU before adding a second monitor to any GPUs.

I’ve added the user to the “video” group for solving the direct rendering problem.

here is the config :

# nvidia-settings: X configuration file generated by nvidia-settings
# nvidia-settings:  version 331.20  (buildmeister@swio-display-x86-rhel47-05)  Wed Oct 30 18:20:32 PDT 2013

Section "ServerLayout"
    Identifier     "Layout0"
    Screen      0  "Screen0" 0 0
    InputDevice    "Keyboard0" "CoreKeyboard"
    InputDevice    "Mouse0" "CorePointer"
    Option         "Xinerama" "0"
EndSection

Section "Files"
EndSection

Section "InputDevice"
    Identifier     "Mouse0"
    Driver         "mouse"
    Option         "Protocol" "auto"
    Option         "Device" "/dev/psaux"
    Option         "Emulate3Buttons" "no"
    Option         "ZAxisMapping" "4 5"
EndSection

Section "InputDevice"
    Identifier     "Keyboard0"
    Driver         "kbd"
EndSection

Section "Monitor"
    Identifier     "Monitor0"
    VendorName     "Unknown"
    ModelName      "Idek Iiyama PL2710HD"
    HorizSync       30.0 - 83.0
    VertRefresh     55.0 - 76.0
    Option         "DPMS"
EndSection

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BoardName      "GeForce GTX 780"
    BusID          "PCI:1:0:0"
EndSection

Section "Device"
    Identifier     "Device1"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BoardName      "GeForce GTX 780"
    BusID          "PCI:2:0:0"
EndSection

Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "Monitor0"
    DefaultDepth    24
    Option         "Stereo" "0"
    Option         "nvidiaXineramaInfoOrder" "DFP-3"
    Option         "MultiGPU" "On"
    Option         "BaseMosaic" "off"
    Option         "SLI" "Mosaic"
    Option         "MetaModes" "DVI-I-1: 1920x1080 +0+0, HDMI-0: 1920x1080 +3840+0, DVI-D-0: 1920x1080 +1920+0"
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection