Page 1 of 2 12 LastLast
Results 1 to 10 of 11

Thread: Dual monitor problem

  1. #1
    Join Date
    Dec 2008
    Location
    Sydney, Australia
    Posts
    1,021

    Default Dual monitor problem

    I realise that for anyone to help me with this I'll have to provide more information but here's the summary of the problem:
    Using Intel Sandy Bridge integrated graphics on a H67 Intel mobo. Working fine on a single monitor, but when I connect a second I just cannot get any video to appear on the second screen.
    Both screens are recognised by xrandr and the KDE Personal Settings display utility. The monitor itself is black, however, going into power saving mode but not complaining about missing signal.
    Xrandr reports the resolution of both monitors as 1280x1024, though the larger one (HDMI2) should be 1920x1200. Attempting to change the resolution with xrandr messes up the display on HDMI1 but produces nothing on HDMI2. Assuming that the size of the Virtual screen might be a problem (xrandr reports this as 1280x1024) I created a xorg.conf file using Xorg - configure in runlevel 3 and defined Virtual as 3200x1280. Restarted X, no bananas (dark HDMI2). Also defined the two monitors in xorg.conf, btw, with correct modes.
    I'd be driven to conclude that the HDMI cable might be faulty if it wasn't for both KDE and xrandr recognising both monitors and correctly reporting supported modes and EDID.
    I'm at the end of my tether. Any ideas?
    And, just to clarify: the "black" HDMI2 works fine in single monitor mode, using a DVI to HDMI cable plugged into the mobo's DVI port (the monitor only has HDMI and D-sub, the mobo HDMI and DVI). HDMI1, in the dual monitor arrangement, has become the primary monitor, plugged into the mobo's DVI port (the monitor only has DVI and D-sub).
    Günter

    Desk: Tumbleweed, KDE 5, AMD Ryzen 5 3400G, 16Gb, 120Gb SSD, 2 SATA.
    Lap: Thinkpad T430, Tumbleweed, Intel i5, 8Gb, SSD.

  2. #2
    Join Date
    Jun 2008
    Location
    Auckland, NZ
    Posts
    23,700
    Blog Entries
    1

    Default Re: Dual monitor problem

    Using Intel Sandy Bridge integrated graphics on a H67 Intel mobo. Working fine on a single monitor, but when I connect a second I just cannot get any video to appear on the second screen.
    Both screens are recognised by xrandr and the KDE Personal Settings display utility. The monitor itself is black, however, going into power saving mode but not complaining about missing signal.
    I've read another thread like this recently, but not sure that there was a solution. You may need to search for bug reports on this, or file one.
    And, just to clarify: the "black" HDMI2 works fine in single monitor mode, using a DVI to HDMI cable plugged into the mobo's DVI port (the monitor only has HDMI and D-sub, the mobo HDMI and DVI). HDMI1, in the dual monitor arrangement, has become the primary monitor, plugged into the mobo's DVI port (the monitor only has DVI and D-sub).
    So, are you saying you can get a successful dual screen operation, if using the DVI port (and converter) with the second monitor? You can set the primary monitor dynamically like this

    Code:
    xrandr --output HDMI0 --primary
    KDE 'System Settings'>>'Display and Monitor' can do the same.

  3. #3
    Join Date
    Dec 2008
    Location
    Sydney, Australia
    Posts
    1,021

    Default Re: Dual monitor problem

    Quote Originally Posted by deano_ferrari View Post
    I've read another thread like this recently, but not sure that there was a solution. You may need to search for bug reports on this, or file one.

    So, are you saying you can get a successful dual screen operation, if using the DVI port (and converter) with the second monitor? You can set the primary monitor dynamically like this

    Code:
    xrandr --output HDMI0 --primary
    KDE 'System Settings'>>'Display and Monitor' can do the same.
    No, sorry, I wasn't very clear there.... I can't get dual monitor to work. The large screen works in single monitor mode, and in my *attempted* dual monitor mode it swaps ports with the smaller monitor. Xrandr reports both as HDMI even though one is plugged into DVI.
    Günter

    Desk: Tumbleweed, KDE 5, AMD Ryzen 5 3400G, 16Gb, 120Gb SSD, 2 SATA.
    Lap: Thinkpad T430, Tumbleweed, Intel i5, 8Gb, SSD.

  4. #4
    Join Date
    Dec 2008
    Location
    Sydney, Australia
    Posts
    1,021

    Default Re: Dual monitor problem

    Here's the xorg.conf I generated (which doesn't seem to "take", see xrandr output below):

    Code:
    Section "ServerLayout"
            Identifier     "X.org Configured"
            Screen      0  "Screen0" 0 0
            InputDevice    "Mouse0" "CorePointer"
            InputDevice    "Keyboard0" "CoreKeyboard"
    EndSection
    
    Section "Files"
            ModulePath   "/usr/lib64/xorg/modules/updates"
            ModulePath   "/usr/lib64/xorg/modules"
            FontPath     "/usr/share/fonts/misc:unscaled"
            FontPath     "/usr/share/fonts/TTF/"
            FontPath     "/usr/share/fonts/OTF/"
            FontPath     "/usr/share/fonts/Type1/"
            FontPath     "/usr/share/fonts/100dpi:unscaled"
            FontPath     "/usr/share/fonts/75dpi:unscaled"
            FontPath     "/usr/share/fonts/URW/"
            FontPath     "/usr/share/fonts/cyrillic:unscaled"
            FontPath     "/usr/share/fonts/misc/sgi:unscaled"
            FontPath     "/usr/share/fonts/truetype/"
    EndSection
    
    Section "Module"
            Load  "dri"
            Load  "vnc"
            Load  "glx"
            Load  "record"
            Load  "dbe"
            Load  "dri2"
            Load  "extmod"
    EndSection
    
    Section "InputDevice"
            Identifier  "Keyboard0"
            Driver      "kbd"
    EndSection
    
    Section "InputDevice"
            Identifier  "Mouse0"
            Driver      "mouse"
            Option      "Protocol" "auto"
            Option      "Device" "/dev/input/mice"
            Option      "ZAxisMapping" "4 5 6 7"
    EndSection
    
    Section "Monitor"
            Identifier   "Monitor0"
            VendorName   "Monitor Vendor"
            ModelName    "Monitor Model"
            Option       "PreferredMode"  "1280x1024" 
            Option       "Primary"    "True"
    EndSection
    
    Section "Monitor"
            Identifier   "Monitor1"
            Option       "PreferredMode"  "1920x1200" 
            Option       "LeftOf" "Monitor0" 
            Option       "Primary"    "False"
    EndSection
    
    Section "Device"
            ### Available Driver options are:-
            ### Values: <i>: integer, <f>: float, <bool>: "True"/"False",
            ### <string>: "String", <freq>: "<f> Hz/kHz/MHz",
            ### <percent>: "<f>%"
            ### [arg]: arg optional
            #Option     "AccelMethod"               # [<str>]
            #Option     "DRI"                       # [<bool>]
            #Option     "ColorKey"                  # <i>
            #Option     "VideoKey"                  # <i>
            #Option     "FallbackDebug"             # [<bool>]
            #Option     "Tiling"                    # [<bool>]
            #Option     "Shadow"                    # [<bool>]
            #Option     "SwapbuffersWait"           # [<bool>]
            #Option     "XvMC"                      # [<bool>]
            #Option     "XvPreferOverlay"           # [<bool>]
            #Option     "DebugFlushBatches"         # [<bool>]
            #Option     "DebugFlushCaches"          # [<bool>]
            #Option     "DebugWait"                 # [<bool>]
            #Option     "HotPlug"                   # [<bool>]
            Identifier  "Card0"
            Driver      "intel"
            BusID       "PCI:0:2:0"
    EndSection
    
    Section "Screen"
            Identifier "Screen0"
            Device     "Card0"
            Monitor    "Monitor0"
            SubSection "Display"
                    Viewport   0 0
                    Depth     1
            EndSubSection
            SubSection "Display"
                    Viewport   0 0
                    Depth     4
            EndSubSection
            SubSection "Display"
                    Viewport   0 0
                    Depth     8
            EndSubSection
            SubSection "Display"
                    Viewport   0 0
                    Depth     15
            EndSubSection
            SubSection "Display"
                    Viewport   0 0
                    Depth     16
            EndSubSection
            SubSection "Display"
                    Viewport   0 0
                    Depth     24
                    Virtual 3200 1280
            EndSubSection
    EndSection
    And here's the output of xrandr -q:

    Code:
    Screen 0: minimum 320 x 200, current 1280 x 1024, maximum 8192 x 8192
    VGA1 disconnected (normal left inverted right x axis y axis)
    HDMI1 connected 1280x1024+0+0 (normal left inverted right x axis y axis) 338mm x 270mm
       1280x1024      60.0*+
       1152x864       75.0  
       1024x768       75.1     75.0     60.0  
       832x624        74.6  
       800x600        75.0     60.3  
       640x480        75.0     60.0  
       720x400        70.1  
    DP1 disconnected (normal left inverted right x axis y axis)
    HDMI2 connected 1280x1024+0+0 (normal left inverted right x axis y axis) 432mm x 324mm
       1920x1200      60.0 +
       1920x1080      60.0  
       1600x1200      60.0  
       1680x1050      60.0  
       1280x1024      75.0     60.0* 
       1280x960       75.0  
       1024x768       75.1     60.0  
       800x600        75.0     60.3  
       640x480        75.0     60.0  
       720x400        70.1  
    DP2 disconnected (normal left inverted right x axis y axis)
    Günter

    Desk: Tumbleweed, KDE 5, AMD Ryzen 5 3400G, 16Gb, 120Gb SSD, 2 SATA.
    Lap: Thinkpad T430, Tumbleweed, Intel i5, 8Gb, SSD.

  5. #5
    Join Date
    Jun 2008
    Location
    Auckland, NZ
    Posts
    23,700
    Blog Entries
    1

    Default Re: Dual monitor problem

    Well this is a likely bug, so if you don't get anywhere, its worth reporting as such.

    In the meantime, maybe try this minimal /etc/X11/xorg.conf

    Code:
    Section "Monitor"
            Identifier   "Monitor0"
            Option       "PreferredMode"  "1280x1024" 
            Option       "Position" "0 0"
            Option       "Primary"    "True"
    EndSection
    
    Section "Monitor"
            Identifier   "Monitor1"
            Option       "PreferredMode"  "1920x1200" 
            Option       "LeftOf" "Monitor0"
            Option       "Position"   "1280 0"
            Option       "Primary"    "False"
    EndSection
    
    Section "Device"
    Identifier "intel"
    Driver "intel"
    Option "monitor-HDMI1" "Monitor0"
    Option "monitor-HDMI2" "Monitor1"
    EndSection

  6. #6
    Join Date
    Dec 2008
    Location
    Sydney, Australia
    Posts
    1,021

    Default Re: Dual monitor problem

    Tried that xorg.conf and no change. Meanwhile I've discovered something else: the 1920x1200 monitor will not work as the sole monitor either if connected HDMI-HDMI, only if HDMI (monitor) to DVI (mobo). When I tried HDMI-HDMI, I didn't even get a BIOS screen. Now if I hadn't seen xrandr and KDE Personal Settings report both monitors as connected when the 1920x1200 was HDMI-HDMI and the 1280x1024 HDMI-DVI, I would say that the HDMI-HDMI cable was suspect and go and get another one. But surely the correct reporting as connected, complete with possible modes, indicates that the cable is working? Or not?
    Unfortunately I don't have another HDMI-DVI cable at hand, or I'd now try to add the second monitor again (mobo only has one HDMI and one DVI, second monitor has DVI and VGA, first monitor HDMI and VGA).
    Günter

    Desk: Tumbleweed, KDE 5, AMD Ryzen 5 3400G, 16Gb, 120Gb SSD, 2 SATA.
    Lap: Thinkpad T430, Tumbleweed, Intel i5, 8Gb, SSD.

  7. #7
    Join Date
    Dec 2008
    Location
    Sydney, Australia
    Posts
    1,021

    Default Re: Dual monitor problem

    Well well well... Found another HDMI-DVI cable (amazing what you accumulate without knowing...), connected second monitor, and hey presto! Had to make minor adjustments in KDE Personal Settings and now have both working fine. Interestingly, during boot both appear to be fighting over which is the primary one, with the BIOS splash on Monitor 2 and the KDE login first on 2 and then also on 1. But I can live with that, for now...
    Probably best to delete that xorg.conf now?
    Günter

    Desk: Tumbleweed, KDE 5, AMD Ryzen 5 3400G, 16Gb, 120Gb SSD, 2 SATA.
    Lap: Thinkpad T430, Tumbleweed, Intel i5, 8Gb, SSD.

  8. #8
    Join Date
    Dec 2008
    Location
    Sydney, Australia
    Posts
    1,021

    Default Re: Dual monitor problem

    Not quite over yet... In my elation, I forgot that I want to rotate the second monitor, so that's next...
    Günter

    Desk: Tumbleweed, KDE 5, AMD Ryzen 5 3400G, 16Gb, 120Gb SSD, 2 SATA.
    Lap: Thinkpad T430, Tumbleweed, Intel i5, 8Gb, SSD.

  9. #9
    Join Date
    Dec 2008
    Location
    Sydney, Australia
    Posts
    1,021

    Default Re: Dual monitor problem

    Now that was easy peasy: KDE Personal Settings/Display handled it beautifully, no need for Xrandr or xorg.conf. Saved defaults and restarted X to see if settings are persistent, and they are. Amazing how much KDE4 has improved (I'm using 4.6.3). Very happy now, and thanks for your help!

    Edited: of course I will need xrandr to have one display spread over both monitors, what I have now is two independent X screens. Might stay with that but of course I can't move windows across now. Then again, if I use one big screen xinerama style, I assume I'll have problems with wallpapers getting stretched across both screens, and maximised application windows?
    Günter

    Desk: Tumbleweed, KDE 5, AMD Ryzen 5 3400G, 16Gb, 120Gb SSD, 2 SATA.
    Lap: Thinkpad T430, Tumbleweed, Intel i5, 8Gb, SSD.

  10. #10
    Join Date
    Dec 2008
    Location
    Sydney, Australia
    Posts
    1,021

    Default Re: Dual monitor problem

    Forget the edit of previous message: I was wrong. It's not two X screens but one desktop spanned across the monitors. Wallpapers and maximised apps behaving impeccably. Great job, KDE!
    Günter

    Desk: Tumbleweed, KDE 5, AMD Ryzen 5 3400G, 16Gb, 120Gb SSD, 2 SATA.
    Lap: Thinkpad T430, Tumbleweed, Intel i5, 8Gb, SSD.

Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •