Is "Separate X Sessions" with NVIDIA a thing of the past?

273 · 05-20-2016, 05:22 PM

I have been running two screens on my desktop using "separate X sessions" through the NVIDIA Settings for a number of years now having started with two graphics cards and now having only the one (GTX 640).
I currently use XFCE and it seems OK but I have noticed issues creeping in* so decided to try other desktops. MATE seems, vaguely, to work but both KDE4 and GNOME3 don't allow me to use the second monitor at all. Does that mean it's one X session or nothing? Would it help if I, again, had two cards?

I ask because as things are I've a 16:10 monitor I use for games and video and a 4:3 one I use mainly for email and a conky. I found without separate X session it was difficult to open an application in one monitor, meant that only one could be used for gaming and that the mouse was less likely to be contained within the game. I do things like a full-screen VLC in one and a game in the other (interchangeably using VLC remote) too. I may acquire more or different monitors but the setup has been, with only a few niggles, pretty much exactly what I wanted.

Any ideas whether I could do this in KDE4 or GOME3 with or without separate X sessions or any tips generally?

*pop-ups for Bluetooth moving across the screen horizontally being the obvious one.

Emerson · 05-22-2016, 08:19 AM

I believe it is possible, just requires hand made xorg.conf.

273 · 05-22-2016, 08:31 AM

Quote:

Originally Posted by Emerson

I believe it is possible, just requires hand made xorg.conf.

I do have the file (contents below) but neither KDE nor GNOME give me the option to do anything with the second screen -- with XFCE and MATE I can use both screens for panels and applications. So my question is have KDE and GNOME stopped supporting separate X sessions and, if not, how do I configure them to use both screens?

Code:

cat /etc/X11/xorg.conf
# nvidia-settings: X configuration file generated by nvidia-settings
# nvidia-settings:  version 331.79  (pbuilder@zam904)  Wed May 21 23:47:59 UTC 2014

# nvidia-xconfig: X configuration file generated by nvidia-xconfig
# nvidia-xconfig:  version 302.17  (pbuilder@cake)  Sat Jun 30 17:25:40 UTC 2012

Section "ServerLayout"
    Identifier     "Layout0"
    Screen      0  "Screen0" 0 0
    Screen      1  "Screen1" RightOf "Screen0"
    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"
    Identifier     "Monitor0"
    VendorName     "Unknown"
    ModelName      "Idek Iiyama PLE2403WS"
    HorizSync       30.0 - 83.0
    VertRefresh     56.0 - 76.0
    Option         "DPMS"
EndSection

Section "Monitor"
    Identifier     "Monitor1"
    VendorName     "Unknown"
    ModelName      "Toshiba Matsushita Display Technology Co., Ltd LCD-MONITOR"
    HorizSync       31.0 - 95.0
    VertRefresh     55.0 - 85.0
EndSection

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BoardName      "GeForce GT 640"
    BusID          "PCI:1:0:0"
    Screen          0
EndSection

Section "Device"
    Identifier     "Device1"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BoardName      "GeForce GT 640"
    BusID          "PCI:1:0:0"
    Screen          1
EndSection

Section "Screen"

# Removed Option "metamodes" "CRT: nvidia-auto-select +0+0"
# Removed Option "nvidiaXineramaInfoOrder" "DFP-0"
# Removed Option "nvidiaXineramaInfoOrder" "CRT-0"
# Removed Option "metamodes" "CRT: nvidia-auto-select +1920+0, DFP: nvidia-auto-select +0+0"
# Removed Option "metamodes" "CRT: nvidia-auto-select +0+0"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "Monitor0"
    DefaultDepth    24
    Option         "nvidiaXineramaInfoOrder" "DFP-0"
    Option         "Stereo" "0"
    Option         "metamodes" "HDMI-0: nvidia-auto-select +0+0"
    Option         "SLI" "Off"
    Option         "MultiGPU" "Off"
    Option         "BaseMosaic" "off"
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection

Section "Screen"
# Removed Option "metamodes" "DFP: nvidia-auto-select +0+0"
    Identifier     "Screen1"
    Device         "Device1"
    Monitor        "Monitor1"
    DefaultDepth    24
    Option         "nvidiaXineramaInfoOrder" "DFP-0"
    Option         "Stereo" "0"
    Option         "metamodes" "VGA-0: nvidia-auto-select +0+0"
    Option         "SLI" "Off"
    Option         "MultiGPU" "Off"
    Option         "BaseMosaic" "off"
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection

Also, as mentioned, I don't see the option for "separate X sessions" in the NVIDIA X settings application so wonder whether it's a deprecated option?

Emerson · 05-22-2016, 08:41 AM

Maybe you should define separate X session. For me this means you start whole new Xorg on secondary monitor with possibly a different DE/WM.
BTW, disabling Xinerama is not a good idea if you want to keep your apps on certain monitor.

273 · 05-22-2016, 08:50 AM

I did already set up separate X sessions -- I did so years ago and haven't changed anything. I allowed the NVIDIA X server setting application to write to my xorg.conf and the results are above. In XFCE things work as they ought. If I were to enable Xinerama (which, now I think about it, I don't appear to have an option for where I thought I did either) then it would make only one X session across both screens which is exacly what I don't want.

Have things changed in the last few years as regards NVIDIA, X sessions and their configuration? As I mentioned for years, including when I ran two cards, I've had pretty much the same setup but when I look at the NVIDIA application the options don't seem to be there any more and both KDE and GNOME don't allow me to use the second screen.
I have also, in the past, ran two DEs one on each monitor but I was also able to use both monitors in one DE but this isn't possible with KDE or GNOME any more. Do neither support this configuration?
Again, is this deprecated? Do NVIDIA not support it either as evidenced by my not seeing it in the setting application or am I looking in the wrong place?

Emerson · 05-22-2016, 09:00 AM

I'm still confused with your separate X sessions term. Using separate X sessions means using different xorg.conf for each one in my book.

273 · 05-22-2016, 09:07 AM

It was the term used in the NVIDIA X server settings dialogue. When using things like Xinerama only one monitor could have 3D acceleration and, with some of the other settings, only one monitor could have panels added.
I think NVIDIA have probably changed how things work now but I don't want to start from scratch with the configuration again and use some new option if things won't work as I want them.
This is why I'm asking about this -- I'm hoping somebody knows what's changed and why and what the new way of doing what I want is.

Emerson · 05-22-2016, 09:20 AM

Oh I see. I use nVidia cards myself, but I never used their configuration utility. It creates bloated and often incompatible (with latest Xorg) configurations IMHO.
Regarding Xinerama. I've learned when an application is built with Xinerama support it will not expand over all monitors. Even when using TwinView Xinerama support is still needed to keep apps on display where they were started. This is my experience with OpenBox. I guess KDE and Gnome go well beyond basics and try to configure and govern everything ...

273 · 05-22-2016, 09:30 AM

The beauty of the "separate X sessions" is that applications only appear on the monitor they're opened on and can't be moved between monitors or maximised across both. I could, and have, use different DEs for each monitor (with my xorg.conf as shown which was created by nvidia-settings but I have also created similar manually) as well.
I don't know what KDE and GNOME are doing or not doing, however, as they only show the one monitor in their display settings.

Emerson · 05-22-2016, 09:52 AM

My configuration is different. I have hand-written xorg.conf, Xinerama enabled. Applications can be moved from one display to another but when maximized they do not expand over both displays. This is the way I like it. BTW, nVidia driver is compatible with xrandr, so you can use it to tune your display.

273 · 06-21-2016, 01:44 AM

Quote:

Originally Posted by Emerson

My configuration is different. I have hand-written xorg.conf, Xinerama enabled. Applications can be moved from one display to another but when maximized they do not expand over both displays. This is the way I like it. BTW, nVidia driver is compatible with xrandr, so you can use it to tune your display.

I'm not sure I'd want tobe able to move application from one screen to another but, if possble, please could you post your xorg.conf? I'm considering getting a new graphics card so may well be messing around with things soon and it would be good to have a known working example.

I'm still puzzled as to why neither Gnome nor KDE can even see the second monitor. Perhaps they don't use xorg.conf any more and rely upon some other method?

Emerson · 06-21-2016, 05:50 AM

Not much to see here, the config below sets up the driver and xrandr is run from ~/.xixnitrc

Code:

xrandr --auto --output DVI-I-3 --left-of DVI-I-2

Code:

~ $ cat /etc/X11/xorg.conf
Section "Files"
    FontPath    "/usr/share/fonts/terminus/"
    ModulePath "/usr/lib32/xorg/modules"
    ModulePath "/usr/lib64/opengl/nvidia"
    ModulePath "/usr/lib64/xorg/modules"
EndSection

Section "Monitor"
    Identifier     "Monitor0"
    VendorName     "Unknown"
EndSection

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
EndSection

Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
    DefaultDepth    24
EndSection

273 · 06-21-2016, 01:10 PM

Thanks, is xrandr used to create one monitor from one then xorg.conf just tells the DE to use that one monitor?
I'm confused as to why, with my current setup, KDE and GNOME don't see my second monitor at all but XFCE uses it fine (well, with slight niggles).

Emerson · 06-21-2016, 01:22 PM

xrandr is used to set my secondary monitor to left, for some reason without xrandr it comes up secondary monitor right. KDE and Gnome ... don't know, my setup is very spartan, plain OpenBox.

273 · 06-21-2016, 01:27 PM

Even stranger, I can't understand your xorg.conf in that case. Are you sure it's even needed and X11 isn't finding them on the fly?
I can understand OpenBox could be more friendly for this setup as it's lighter and more configurable.