enabling X server backing store (Ubuntu 11.04 guest)

[krthie]

Hi

I'm not 100% sure if this is a virtualbox issue, but no doubt someone can tell me

I am running Ubuntu 11.04 as guest on Virtualbox 4.1.10 on Windows 7 Pro.

I need to change the X windows server settings to enable backing store for some old application that I have. I have spent some time trawling through the internet and tried a few different things, but apparently all to no avail. xdpyinfo still reports

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 options:    backing-store NO, save-unders NO


Here's what I tried. i modified /etc/X11/xorg.conf and put

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option "backingstore" "on"

in a few places:

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Section "Device"
  BoardName    "VirtualBox Graphics"
  Driver       "vboxvideo"
  Identifier   "Device[0]"
  VendorName   "Oracle Corporation"
  Option   "backingstore" "on"
EndSection

Section "Screen"
  SubSection "Display"
    Depth      24
  EndSubSection
  Device       "Device[0]"
  Identifier   "Screen[0]"
  Monitor      "Monitor[0]"
EndSection
Section "ServerLayout"
        Identifier      "Device[0]"
#        Screen          "Screen[0]"
    Option "BackingStore" "on"
EndSection


I've also created a file /usr/share/X11/xorg.conf.d/05-backingstore.conf with the content of the ServerLayout as above, just in case.

I do know that the X server is using the modified file, because when I make a mistake, it tells me so. By the way, I've tried a variety of ways to restart the xserver. The quickest seems to be

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sudo service lightdm restart


but a complete reboot of the guest also didn't fix my problem.

So, now I don't know what to do anymore. I confess that I don't know if the "backingstore" is implemented by the X server, or by the driver (i.e. virtualbox in this case).

Any help would be greatly appreciated.

Many thanks

[krthie]

The fact that setting this in xorg.conf doesn't work might be an Xorg issue.

I've found out that I can enable backingstore by using the +bs option to X (e.g. in my ~/.xserverrc for startx, or in /etc/lightdm/lightdm.conf by using xserver-command=X +bs).

This works according to xdpyinfo, so I guess this wasn't a VirtualBox issue at all.

Sadly it doesn't fix my application, which now just displays a black window. Oh well.