Centos 5.4 with Guest Additions has only 800x600 resolution

[gregdavisfromnj]

Bottom Line, how do you configure the X resolution on a CentOS guest with Guest Additions loaded to be arbitrary (albiet statically defined in an xorg.conf)?

Skulking around, I've found that dynamic resizing doesn't work in xserver less than 1.3, and the latest CentOS (5.4 as of this) uses 1.1.1. The GA installer informs me of this, changes the xorg.conf nonetheless, and my xserver tries to restart. It fails, without a reason. The video driver is set to vboxvideo, and there are no errors or warnings in the Xorg.0.log file.

So I try to change the Xorg video driver to "vesa". This lets the xserver start, but the display is limited to a resolution of 800x600, or 800x600 in a viewport that is 640x480. This is quite annoying. The Xorg.0.log file in this case complains about not being able to use DDC, and the VESA driver seems to be aware that the guest is in fact running in VirtualBox, but no errors. I added some Modes higher than 800x600 to the xorg.conf Screen section, but these are ignored. At least, they might be out of the guessed hsync/vsync range by the vesa driver.

I tried wierd things like resizing the window containing the guest before restarting X, so that it might guess at a bigger screen geometry. I tried some strange voodoo incantations using VBoxManage and "GUI/MaxGuestResolution" or setvideomodehint. No change.

I can't be the only person in the world that wants to run CentOS 5.4 as a guest with a resolution higher than 800x600.

Thanks

[Perryg]

Edit the /etc/X11/xorg.conf and add something like this.

Code: Select all

Section "Screen"
       Identifier "Screen0"
       Device     "Videocard0"
       DefaultDepth     24
       SubSection "Display"
               Viewport   0 0
               Depth     24
               Modes    "1750x1090" "1600x1200" "1600x1024" "1440x900" "1400x1050" "1280x1024" "1280x960" "1280x800" "1152x864" "1152x768" "1024x768" "800x600" "640x480"
       EndSubSection
EndSection

[gregdavisfromnj]

It looks like you are suggesting adding the Modes line. I tried that, and it is either ignored, or the modes outside of the virtual monitor's range are ignored. What should the Monitor and Device sections look like?

Thanks

[Perryg]

Here is my working xorg.conf (complete)

Code: Select all

# VirtualBox generated configuration file
# based on /etc/X11/xorg.conf.
# Xorg configuration created by pyxf86config

# Section "ServerLayout"
# 	Identifier     "Default Layout"
# 	Screen      0  "Screen0" 0 0
# 	InputDevice    "Keyboard0" "CoreKeyboard"
# EndSection

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

# Section "Device"
# 	Identifier  "Videocard0"
# 	Driver      "vesa"
# EndSection

# Section "Screen"
# 	Identifier "Screen0"
# 	Device     "Videocard0"
# 	DefaultDepth     24
# 	SubSection "Display"
# 		Viewport   0 0
# 		Depth     24
# 	EndSubSection
# EndSection

Section "InputDevice"
  Identifier   "Keyboard[0]"
  Driver       "kbd"
	Option	    "XkbModel" "pc105"
	Option	    "XkbLayout" "us"
  Option       "Protocol" "Standard"
  Option       "CoreKeyboard"
EndSection

Section "InputDevice"
  Identifier  "Mouse[1]"
  Driver      "vboxmouse"
  Option      "Buttons" "9"
  Option      "Device" "/dev/input/mice"
  Option      "Name" "VirtualBox Mouse"
  Option      "Protocol" "explorerps/2"
  Option      "Vendor" "Sun Microsystems Inc"
  Option      "ZAxisMapping" "4 5"
  Option      "CorePointer"
EndSection

Section "ServerLayout"
  Identifier   "Layout[all]"
  InputDevice  "Keyboard[0]" "CoreKeyboard"
  InputDevice  "Mouse[1]" "CorePointer"
  Option       "Clone" "off"
  Option       "Xinerama" "off"
  Screen       "Screen[0]"
EndSection

Section "Monitor"
  Identifier   "Monitor[0]"
  ModelName    "VirtualBox Virtual Output"
  VendorName   "Sun Microsystems Inc"
EndSection

Section "Device"
  BoardName    "VirtualBox Graphics"
  Driver       "vboxvideo"
  Identifier   "Device[0]"
  VendorName   "Sun Microsystems Inc"
EndSection

Section "Screen"
  SubSection "Display"
    Depth      24
    Modes    "1750x1090" "1600x1200" "1600x1024" "1440x900" "1400x1050" "1280x1024" "1280x960" "1280x800" "1152x864" "1152x768" "1024x768" "800x600" "640x480"
  EndSubSection
  Device       "Device[0]"
  Identifier   "Screen[0]"
  Monitor      "Monitor[0]"
EndSection

Then after a reboot they become available in the screen resolution section. There you should be able to pick what ever size you want. Add the proper size you want to the list if it is not there and delete the ones you do not need.

Centos5-4-Res.jpg (20.21 KiB) Viewed 12886 times

[Perryg]

(In CentOS 5.4) You may need to go into the system->administration->display and define your monitor to be able to use the full range of display.

[gregdavisfromnj]

I am not sure of the magic I performed, but I found that the CentOS Display Resolution tool would edit the xorg.conf file to remove valid modes after I had selected one, and so they were mysteriously disappearing! I also had to have the 800x600 and 640x480 modes in the xorg.conf file, in addition to the ones I actually wanted. Other wise, X wouldn't start.

So to switch resolutions without editing the xorg.conf file, I am hitting left-ctrl + left-alt + '+' or '-' on the numberpad. But, this is just giving me a scrolling viewport.

All this seems like it would be much easier if the Xserver in CentOS supported Xrandr. Maybe when RHEL 6 is released? I digress. Thanks for the help.

[shalom938]

The voodoo worked for me with centos 5.5. after reading this post I closed all windows, clicked restart and immediately hit right C+f to resize the vm window. when the vm restarted i had all the possible resolutions in centos.

[Technologov]

People - you do something wrong.

RHEL 5.x is fully supported by VirtualBox 3.2.0 -- including dynamic resolution resizing and custom resolutions.

gregdavisfromnj : Please update VBox.

[cicoub13]

Thanks a lot (works for Red Hat Enterprise Linux 6)