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Re: [Xen-users] Paravirtualized Linux with graphics (X Window)?

Jeff Lane wrote:
On Fri, Feb 27, 2009 at 12:33 AM, NAHieu <nahieu@xxxxxxxxx> wrote:
On Fri, Feb 27, 2009 at 1:09 PM, Javier Guerra Giraldez
<javier@xxxxxxxxxxx> wrote:
NAHieu wrote:
I use "usbdevice='tablet'", but that doesnt help. My guest run Ubuntu 8.04.
Try this...

Log into your VM using your now working VNC and open a console.  Use
xset like this:

xset m 0 0

Which should completely turn off mouse acceleration.  You may have to
move your mouse outside the domU window and back to get it to take
effect, but that should sync the black dot and the mouse pointer in
the domU VNC window.

That's part way towards a cure.

To get something that works completely you'll need a slightly different approach. What I'm describing is what I've done on a Fedora 8 system, but the same will apply for Ubuntu 8.04 I think.

What you're aiming to do is replace the X mouse pointer with something that understands the absolute coordinates that the VNC pointer really wants ... let's cut to the chase.

On my system I look at /proc/bus/input/devices and in there there's a stanza like this:

   I: Bus=0001 Vendor=5853 Product=fffe Version=0000
   N: Name="Xen Virtual Pointer"
   P: Phys=xenbus/device/vkbd/0
   S: Sysfs=/class/input/input2
   H: Handlers=mouse1 event2 js0
   B: EV=f
   B: KEY=ff0000 0 0 0 0 0 0 0 0
   B: REL=3
   B: ABS=3

If you have a combined pointer and keyboard device you need something more complicated and probably a patch so I'll assume that you have this (you probably do).

Chances are that what you have is _exactly_ what I have, even down to the S: and H: lines. These lines refer to "input2" and "event2" and both tell us that the Xen Virtual Pointer is attached to the file /dev/input/event2.

Armed with this you can now edit /etc/X11/xorg.conf. I forget what Ubuntu has in there, but there's probably an InputDevice section that refers to a mouse, change it to look something like this:

   Section "InputDevice"
       Identifier      "Mouse0"
       Driver          "evdev"
       Option          "Device" "/dev/input/event2"

The identifier should be whatever you already have, the Driver and Option lines need to be changed to match mine (except that the /dev/input/event2 might need to be changed to match what shows up in /proc/bus/input/devices).

When you've done that, restart X and, with a little luck, it will all work.

If it doesn't, check /var/log/Xorg.0.log. It will either tell you (eventually) that you've got some spelling mistake somewhere or that you're missing the evdev driver. On Fedora that's in an rpm called xorg-x11-drv-evdev, but you'll have to go hunting with synaptic on Ubuntu.

Hope that helps.


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