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

John Haxby
2009-02-27T16:15:43Z

Jeff Lane wrote:
> On Fri, Feb 27, 2009 at 12:33 AM, NAHieu <nahieu@gmail.com> wrote:
>
>> On Fri, Feb 27, 2009 at 1:09 PM, Javier Guerra Giraldez
>> <javier@guerrag.com> 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"
    EndSection

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.

jch