A question about new X screens...

trist007 · 03-28-2014, 11:50 AM

I am running Slackware 64 14.1. I have three monitors all on one X screen. I have decided to break it up into 3 X screens. I have an Nvidia graphics card with the nvidia module installed from Nvidia's website.

The weird thing is that when I use the nvidia-settings program and set each monitor be a separate X screen and I hit "apply" or I reload X, the font size on the screens shrink to almost nothing. At that point trying to read the settings in nvidia-settings is nearly impossible because the font size is soo small.

What gets changed to bring the font size that small? Where can I modify that setting?

trist007 · 03-29-2014, 01:17 AM

It was the dpi after all. I modified the /usr/bin/startx script

defaultserverargs="-dpi 96"

That fixed it!

This leads me to another question. I've never fully understood this. If I have 3 X screens, I can set the DISPLAY environmental variable so that full screen applications like wine play games on that particular monitor. Also need to be able to move windows between X screens seamlessly. So I turned on Xinerama, but man it caused lots of issues.

So for X screen 2, I could do DISPLAY=:1.0. That's what I was thinking but if I do that and try to start an application it just says to make sure my DISPLAY environmental variable is setup correctly.

Before I had all 3 monitors as one X screen. I tried setting DISPLAY=:0.1 to start full screen applications to start on that monitor but I would get the same error, that my DISPLAY was not setup correctly.

What do you guys recommend besides switching DVI cables to the monitor I want.

allend · 03-29-2014, 06:19 AM

Have you looked at the documentation in /usr/doc/NVIDIA_GLX-1.0?
I have:
Chapter 13. Configuring Multiple Display Devices on One X Screen
Chapter 14. Configuring GLX in Xinerama
Chapter 15. Configuring Multiple X Screens on One Card

I only have two monitors, but I have a /etc/X11/xorg.conf file that provides for four possible layouts. (I do not bother with Xinerama as TwinView works best for me.)
I can choose which layout to use by typing 'startx -- -layout <Layout_Identifier>'
Layouts 0,1,2 only give DISPLAY=:0.0 while Layout3 gives DISPLAY=:0.0 and DISPLAY=:0.1

I happen to use Layout3 as my default with WindowMaker (recent KDE and XFCE have taken to assuming that they need to control all available X screens) as I often work with one monitor continuously showing an open document while I am flipping between applications and workspaces on the other monitor. I cannot drag windows between X screens doing this, but that does not bother me.

Code:

# X configuration file 

Section "ServerFlags"
    Option "DefaultServerLayout"     "Layout3"
EndSection

# Single screen on Monitor0
Section "ServerLayout"
    Identifier     "Layout0"
    Screen      0  "Screen0" 0 0
EndSection

# Single screen on Monitor1
Section "ServerLayout"
    Identifier     "Layout1"
    Screen      0  "Screen1" 0 0
EndSection

# Dual screens on Monitor0 and Monitor1 with TwinView enabled
Section "ServerLayout"
    Identifier     "Layout2"
    Screen      0  "Screen3" 0 0
EndSection

# Dual screens on Monitor0 and Monitor1 with TwinView disabled
Section "ServerLayout"
    Identifier     "Layout3"
    Screen      0  "Screen0" 0 0
    Screen      1  "Screen2" RightOf "Screen0"
EndSection

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BoardName      "GeForce 7300 LE"
    BusID          "PCI:1:0:0"
    Screen          0
EndSection

Section "Device"
    Identifier     "Device1"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BoardName      "GeForce 7300 LE"
    BusID          "PCI:1:0:0"
    Screen          1
EndSection

Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "Monitor0"
    DefaultDepth    24
    Option         "TwinView" "Off"
    Option         "UseDisplayDevice" "DFP-0"
    Option         "metamodes" "DFP: nvidia-auto-select +0+0"
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection

Section "Screen"
    Identifier     "Screen1"
    Device         "Device0"
    Monitor        "Monitor1"
    DefaultDepth    24
    Option         "TwinView" "Off"
    Option         "UseDisplayDevice" "CRT-0"
    Option         "metamodes" "CRT: nvidia-auto-select +0+0"
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection

Section "Screen"
    Identifier     "Screen2"
    Device         "Device1"
    Monitor        "Monitor1"
    DefaultDepth    24
    Option         "TwinView" "Off"
    Option         "UseDisplayDevice" "CRT-0"
    Option         "metamodes" "CRT: nvidia-auto-select +0+0"
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection

Section "Screen"
    Identifier     "Screen3"
    Device         "Device0"
    Monitor        "Monitor0"
    DefaultDepth    24
    Option         "TwinView" "On"
    Option         "UseDisplayDevice" "CRT-0, DFP-0"
    Option         "metamodes" "DFP: nvidia-auto-select +0+0, CRT: nvidia-auto-select +1280+0"
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection

Section "Monitor"
    Identifier     "Monitor0"
EndSection

Section "Monitor"
    Identifier     "Monitor1"
EndSection

Section "Extensions"
    Option         "Composite" "Enable"
EndSection

trist007 · 03-29-2014, 10:08 PM

That's a cool feature. Thanks for the info.