virtualbox.org

We have production machines running RedHat RHEL 5.11 / X version 7.1.1. The supplier of these machines provides a VirtualBox VM to allow software development on conventional computers, i.e. away from the production floor. I would like to configure this VM for dual head / dual monitor / dual screen usage.

Step 1: The VM in VirtualBox Manager is configured for maximum video memory and 2 monitors.

Step 2: VirtualBox GuestAdditions are installed, version corresponding to the Virtual Box application.

Step 3: /etc/X11/xorg.conf is modified to support 2 devices, 2 screens and 2 monitors, all configured for the vboxvideo driver. The content is shown below:

Code: Select all

# Xorg configuration created by system-config-display

Section "ServerLayout"
    Identifier     "Multihead layout"
    Screen      0  "Screen0" 0 0
    Screen      1  "Screen1" RightOf "Screen0"
    InputDevice    "Keyboard0" "CoreKeyboard"
EndSection

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

Section "Monitor"
    Identifier   "Monitor0"
    VendorName   "Monitor Vendor"
    ModelName    "LCD Panel 1600x1200"
EndSection

Section "Monitor"
    Identifier   "Monitor1"
    VendorName   "Monitor Vendor"
    ModelName    "LCD Panel 1600x1200"
EndSection

Section "Device"
    Identifier  "Videocard0"
    Driver      "vboxvideo"
    BusID       "PCI:0:2:0"
    Screen      0
EndSection

Section "Device"
    Identifier  "Videocard1"
    Driver      "vboxvideo"
    BusID       "PCI:0:2:1"
    Screen      1
EndSection

Section "Screen"
    Identifier "Screen0"
    Device     "Videocard0"
    Monitor    "Monitor0"
    DefaultDepth     24
    SubSection "Display"
            Viewport   0 0
            Depth     24
            Modes    "1600x1200" "1280x1024" "1280x960" "1280x800" "1152x864" "1024x768" "800x600" "640x480"
    EndSubSection
EndSection

Section "Screen"
    Identifier "Screen1"
    Device     "Videocard1"
    Monitor    "Monitor1"
    DefaultDepth     24
    SubSection "Display"
            Depth     24
            Modes    "1600x1200" "1280x1024" "1280x960" "1280x800" "1152x864" "1024x768" "800x600" "640x480"
    EndSubSection
EndSection

Step 4: reboot the system

I expect now that the system is set-up and ready to show two screens on my computer. Alas, it only shows Screen0.

Observations:

/var/log/Xorg.0.log shows no errors, but a couple of warnings:
(WW) VBoxVideo(0): Failed to set up write-combining range (0xe0000000,0x8000000)
In the same log file, only the instance VBoxVideo(0) is mentioned; there is no reference to VBoxVideo(1)
lspci also shows only one instance of the VBox video driver:
00:02.0 VGA compatible controller: InnoTek Systemberatung GmbH VirtualBox Graphics Adapter
In VB Manager -> View only Virtual Screen 0 is said to be enabled; the other screen is available, but an "enable" option is presented, that appears to do nothing when selected.
Everything else I have seen seems to be consistent: the second screen is nowhere found on my RHEL VM.

Questions:

What is the importance of the warning on write-combining? Is this related to this problem?
Is vboxvideo driver / pseudo card a dual head card or should I instantiate a second card? What are the correct magic numbers for the BusID of the second "Device"?
Any other recommendation to get this configuration up-n-running?

Start the VM from cold-boot (not from a paused or saved state) / Login / Observe error / Shutdown the VM.
With the VM completely shut down (not paused or saved), right-click on the VM in the VirtualBox Manager and select "Show Log".
Save only the first "VBox.log", ZIP it and attach it to your response (see the "Upload attachment" tab below the reply form).

Dear Socratis, Please find the log file attached. Thanks, Paul

I'm sorry, but I see 4 monitors configured:

00:00:01.970036 MonitorCount <integer> = 0x0000000000000004 (4)
...
00:00:02.800321 GUI: UIMachineViewNormal::resendSizeHint: Restoring guest size-hint for screen 0 to 1280x800
00:00:02.800392 VMMDev: SetVideoModeHint: Got a video mode hint (1280x800x32)@(0x0),(1;0) at 0
00:00:02.800444 GUI: UIMachineViewNormal::resendSizeHint: Restoring guest size-hint for screen 1 to 0x0
00:00:02.800461 VMMDev: SetVideoModeHint: Got a video mode hint (0x0x0)@(0x0),(0;0) at 1
00:00:02.800474 GUI: UIMachineViewNormal::resendSizeHint: Restoring guest size-hint for screen 2 to 800x600
00:00:02.800485 VMMDev: SetVideoModeHint: Got a video mode hint (800x600x0)@(0x0),(0;0) at 2
00:00:02.800494 GUI: UIMachineViewNormal::resendSizeHint: Restoring guest size-hint for screen 3 to 800x600
00:00:02.800503 VMMDev: SetVideoModeHint: Got a video mode hint (800x600x0)@(0x0),(0;0) at 3

And that's the last reference I see in the VBox.log about multiple screens. Can you please post the .vbox file for that VM? Right-click on the VM in VirtualBox Manager, Show in ...(something). ZIP that .vbox file and attach it. Oh, and can you please check the VirtualBox Preferences » Display » Maximum Guest Screen Size? What's it set at?

Unforunately, I'm not that familiar with the proper syntax of the xorg.conf file, so, unless a more Linux oriented user has any comments, I'll have to hit the books search engines...

Dear Soctratis, you're right. VirtualBox was still configured to support up to 4 screens. I've changed that now, so that all references should be 2 screens. Please find attached the zip file containing the Vbox definition and the corresponding log file.

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