Thursday, April 19, 2012

USB/DisplayLink adapter and Fedora 15/16

Two Monitors:  Good!  


Because!   Actually I started using dual monitors on my work rig and things to be  'better'  (2 monitors are better than 1).    Then, after seeing an extra 19" LCD laying around unused, I thought "that should be even better, right?".  

But, my work rig couldn't drive another monitor with out an additional adapter.  For lots reasons, I didn't want to crack my rig's case and work wasn't  going to buy me another adapter any way (they didn't even provide the 2nd monitor; that was on my nickel) a USB adapter somehow made sense.    I decided to proto-type first.


  • Fedora 15 on 32 bit intel hardware with nVidia GPUs.   Today's victim: Dell D820 Latitude with NVS 110M Graphics, 4gb ram, and T2500 cpu.   
  • Diamond BVU 195 from Newegg 
  • Extra LCD.   Today's victim Samsung 25.5" monitor/TV with 1920x1080 res:   model: T260HD
  • Google and Interwebs 

 Here is what I did (first try):

  1. On f15, yum up display link driver. 
  2. Google up what others are doing
  3. Learn lots about xorg.conf that I have been avoiding for years, and thought would go away.   xorg.conf does go away for all but the most simple cases (in modern Linux distros)  
  4. Futz around for long time and find out things don't work 
  5. Did I say I was using gnome3?   
  6. Put project aside for 3 weeks. 

 Here is what I did next (second try):

  1. Restart with new vigor. 
  2. More futzing.    
  3. Find out that BVU 195 and all displaylink devices for linux  lack 3d support (hmm, there goes gnome3 and cinnamon) 
  4. Try to get it to work with gnome3 even after being warned.   Waist time. 
  5. Think maybe gnome3.whatever in F16 might work better that what is comes with f15 (not willing to wait for f17); upgrade to f16  (maybe I will babble  about that  a different day). 
  6. Nope!
  7. Punt on fancy compositing & 3d WMs and desktop environments, yum up XFCE!
  8. Minor screwing around!    It works!   Not perfect, but works.   Here is my xorg.conf. 

Section "ServerLayout"
 Identifier " Configured"
 Screen 0 "MainScreen" 0 0
 Screen 1 "DisplayLinkScreen" LeftOf "MainScreen"
 InputDevice "Mouse0" "CorePointer"
 InputDevice "Keyboard0" "CoreKeyboard"
 Option "Xinerama" "off"
 Option "Clone" "off"

Section "Module"
 #Load "dri2"
 #Load "dri"
 Load "extmod"
 Load "record"
 #Load "glx"
 #Load "dbe"
 Load "fbdevhw"
 Load "displaylink"
 Load "nouveau"

Section "Extensions"
    Option "Composite" "Disable"

Section "InputDevice"
    # generated from default
    Identifier     "Mouse0"
    Driver         "mouse"
    Option         "Protocol" "auto"
    Option         "Device" "/dev/input/mice"
    Option         "Emulate3Buttons" "no"
    Option         "ZAxisMapping" "4 5"

Section "InputDevice"
    Identifier     "Keyboard0"
    Driver         "kbd"
    Option         "XkbLayout" "us"
    Option         "XkbModel" "pc105"

Section "Files"
 ModulePath "/usr/lib/xorg/modules"
 FontPath "catalogue:/etc/X11/fontpath.d"
 FontPath "built-ins"

Section "Monitor"
 Identifier "LaptopMonitor"
 VendorName "DELL"
 Option "DPMS"
 Option "Primary" "True"

Section "Monitor"
 Identifier "DisplayLinkMonitor"

Section "Device"
 Identifier "OnboardGraphix"
 Option "FlatPanel" "True"
 #Option "DualHead" "True"
 #Option  "MergedFB" "True"
 Driver "nouveau"
 BusID "PCI:1:0:0"
 Option "DP-2" "LaptopMonitor"

Section "Device"
 Identifier "DisplayLinkDevice"
 driver "displaylink"
 #Option "MergedFB" "true
 Option "fbdev" "/dev/fb1"

Section "Screen"
 Identifier "DisplayLinkScreen"
 Device "DisplayLinkDevice"
 Monitor "DisplayLinkMonitor"
 SubSection "Display"
  Depth 24

Section "Screen"
 Identifier "MainScreen"
 Device "OnboardGraphix"
 Monitor "LaptopMonitor"
 SubSection "Display"
  Depth 24

Future Direction: 

  • Work rig:  some dell workstation with  Q9450 cpu & Quadro NVS 290, 4gb ram and fedora 15 (32bit).   It does have dual ports for 2 monitors.   I have been happily running 2 monitors for 6 months or so (with gnome3)
  • 3 heads:  2 are already driven by the  Quadro NVS 290.   Add in the BVU 195. 

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