multiple monitors - Could not set the configuration for crtc 79 on Ubuntu

05
2014-04
  • clever_trevor

    I am running Ubuntu with another monitor connected to my laptop so I can extend my desktop. Most the time when I resume the machine, only the second monitor will stay on and I will have to manually turn on the other monitor(the laptop) by going into Screen Display. When this happens, I receive an error that "Could not set the configuration for crtc 79". How can I get the laptop to wake up and keep both its screen and the attached monitor on?

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    Related Question

    Configuring three monitors with two Radeon X1600/X1650 graphics cards under Ubuntu
  • cpm

    I have three SyncMaster 932a monitors I want to use with two Radeon X1600/X1650 cards under Linux.

    I am running X.org X Server 1.6.0, as provided by Ubuntu's Wubi installer.

    After turning off mirroring, I ended up with this xorg.conf:

    Section "Monitor"
            Identifier      "Configured Monitor"
    EndSection
    
    Section "Screen"
           Identifier      "Default Screen"
           Monitor         "Configured Monitor"
           Device          "Configured Video Device"
           SubSection "Display"
                   Virtual 2560 1024
           EndSubSection
    EndSection
    
    Section "Device"
           Identifier      "Configured Video Device"
    EndSection
    

    The left monitor had a menu bar and a task bar, the center monitor was just desktop, and windows would maximize to the current monitor. The third monitor and second graphics card weren't being used at all.

    Then I changed my configuration to manually specify each card with their PCI bus:

    Section "ServerLayout"
            Identifier      "TheLayout"
            Screen          0 "Radeon Screen 1"
            Screen          1 "Radeon Screen 2" RightOf "Radeon Screen 1"
    EndSection
    
    Section "Screen"
            Identifier      "Radeon Screen 1"
            Monitor         "Configured Monitor"
            Device          "Radeon the First"
            SubSection "Display"
                    Virtual 2560 1024
            EndSubSection
    EndSection
    
    Section "Screen"
            Identifier      "Radeon Screen 2"
            Monitor         "Configured Monitor"
            Device          "Radeon the Second"
    EndSection
    
    
    Section "Device"
            Identifier      "Radeon the First"
            Driver          "radeon"
            BusID           "PCI:1:0:0"
    EndSection
    
    Section "Device"
            Identifier      "Radeon the Second"
            Driver          "radeon"
            BusID           "PCI:2:0:0"
    EndSection
    
    Section "Monitor"
            Identifier      "Configured Monitor"
    EndSection
    

    Now both the left and right monitors have task bars and menu bars. Windows cannot be dragged from the first two monitors to the third monitor. Also, maximizing in the left or center window fills both monitors.

    I also tried adding Option "Xinerama" "true" to the ServerLayout section. X11 wasn't able to start up.

    I want to:

    1. Allow moving windows along all three monitors.
    2. Maximizing only fills the current monitor.
    3. Either have menu/task bars on only the left monitor or all three monitors

    How can I make this possible?


  • Related Answers
  • chomsky

    Try xrandr or its arandr interface