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  1. #1

    Graphics card single display fine but no 2nd display


    Hi,

    I've running Mint 18.2 Sonya, its a fairly old tower system Im using but it has always ran dual monitors under Windows.

    When I connect a 2nd monitor I can see it in Displays, it correctly identifies that the monitor is connected and shows the correct details (Acer 19") however nothing displays on the monitor.

    I've tried changing the display settings including Mirroring and setting it as the main display but nothing.

    Ive swapped cables so its my main monitor and it springs into life so the monitor itself is working.

    The working monitor is using a VGA to VGA lead while the 2nd one uses DVI-I to VGA (which worked fine with this Graphics card on Windows 8 ).

    Heres the details when i check the graphics card
    Code:
    $ lshw -numeric -C display
    WARNING: you should run this program as super-user.
      *-display               
           description: VGA compatible controller
           product: Caicos [Radeon HD 6450/7450/8450 / R5 230 OEM] [1002:6779]
           vendor: Advanced Micro Devices, Inc. [AMD/ATI] [1002]
           physical id: 0
           bus info: pci {at} 0000:01:00.0
           version: 00
           width: 64 bits
           clock: 33MHz
           capabilities: vga_controller bus_master cap_list rom
           configuration: driver=radeon latency=0
           resources: irq:27 memory:d0000000-dfffffff memory:febe0000-febfffff ioport:ec00(size=256) memory:c0000-dffff
    Any attempt to update the driver says it is already installed.


    Anyone have any ideas?

  2. #2
    Linux Guru Segfault's Avatar
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    The tool to manage displays is called xrandr.

  3. #3
    Quote Originally Posted by Segfault View Post
    The tool to manage displays is called xrandr.
    Thanks,

    I gave xrandr a go and it correctly identified the two monitors however attempting to start the 2nd still doesnt work.

    I've tried numerous different attempts at
    xrandr --output DVI-0 --auto

    and each time you hear the HD whirring away for a few seconds the command line appears without any error messages but still no joy. If I remove the DVI cable from the graphics card then screen 1 goes off for a second, comes back on and resizes correctly. It then no longer shows in xrandr.

    Plugging it back in shows up in xrandr but still nothing changes. Heres what querying xrandr returns:
    Code:
    $ xrandr -q
    Screen 0: minimum 320 x 200, current 1680 x 1050, maximum 16384 x 16384
    HDMI-0 disconnected (normal left inverted right x axis y axis)
    DVI-0 connected 1280x960+0+0 (normal left inverted right x axis y axis) 410mm x 257mm
       1280x1024     75.02    60.02  
       1440x900      74.98    60.07  
       1280x960      60.00* 
       1152x921      76.03  
       1280x800      74.93    59.81  
       1152x864      75.00  
       1024x768      75.03    70.07    60.00  
       832x624       74.55  
       800x600       72.19    75.00    60.32    56.25  
       640x480       75.00    72.81    66.67    59.94  
       720x400       70.08  
    VGA-0 connected primary 1680x1050+0+0 (normal left inverted right x axis y axis) 474mm x 296mm
       1680x1050     59.95*+
       1600x1200     60.00  
       1400x1050     59.98  
       1280x1024     75.02  
       1440x900      74.98    59.89  
       1280x960      60.00  
       1360x768      59.80  
       1152x864      75.00  
       1024x768      75.03    70.07    60.00  
       832x624       74.55  
       800x600       72.19    75.00    60.32    56.25  
       640x480       75.00    72.81    66.67    59.94  
       720x400       70.08
    I get the same output before and after running --output

    $ xrandr --listmonitors

    gives me
    Code:
     0: +*VGA-0 1680/474x1050/296+0+0  VGA-0
     1: +DVI-0 1280/410x960/257+0+0  DVI-0

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  5. #4
    Linux Guru
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    there's a simple graphical frontend to xrandr, called arandr. i've been using that for, like, ever. try it, it's more intuitive (mouse and menu driven).

  6. #5
    Quote Originally Posted by nihili View Post
    there's a simple graphical frontend to xrandr, called arandr. i've been using that for, like, ever. try it, it's more intuitive (mouse and menu driven).
    Cheers,

    Ive just given that a go and I can see both monitors but when I right click over them they are both shown as Active with the VGA also showing Primary (as I would expect).

    I dont then seem to be able to do anything other than move the screens round and make them Active/Disabled.

  7. #6
    Linux Guru Segfault's Avatar
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    > however nothing displays on the monitor

    What's that. Does it mean the backlight goes off? In any case, there should be clues in Xorg log.

  8. #7
    Linux Newbie sarlacii's Avatar
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    Quote Originally Posted by nihili View Post
    there's a simple graphical frontend to xrandr, called arandr. i've been using that for, like, ever. try it, it's more intuitive (mouse and menu driven).
    As an aside - didn't know about arandr. Thanks... sometimes a GUI is just easier to fiddle with. Ta.

  9. #8
    -->
    Quote Originally Posted by Segfault View Post
    > however nothing displays on the monitor

    What's that. Does it mean the backlight goes off? In any case, there should be clues in Xorg log.
    Nothing happens at all, the monitor has its orange power light which never changes (should turn blue when on), its as if its not plugged into the PC at all. Theres no change in the state of the monitor on any action I take.

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