[Fedora-xen] Mouse out of sync on guest machines

[Robert Thiem]

>    1. Mouse out of sync on guest machines (Filipe Miranda)
> Anyway, everything worked just fine, but I noticed the the my mouse
> pointer
> is totally out of sync in either text mode or graphic mode.
> Is anyone having the same issue? Or is it a bug? or a misconfiguration?

I was pretty traumatised by this when I first ran the FC6 guest install.

It works like this:
- X drivers on the guest are expecting regular mouse movement signals (eg
"The mouse is moving left, fast")
- VNC provides absolute mouse coordinates (X,Y)
- XenFB tries to translate the two, but can't sync the pointers well
because it gets no signals back from the guest about the absolute position
and pointer accelleration.

After installation the mouse pointers can be aligned pretty well by
setting the mouse accelleration on the guest so that they move at the same
rate. You then need to chase the pointer into a corner to align them. This
way the guest accelleration matches the arbitrary value XenFB is using.

During installation I've found it's best to turn the mouse accelleration
right down on the *host*. I found that this would let me move the *host*
mouse pointer to the middle of the VNC window to give me fairly free
movement on the guest pointer.

Unfortunately this is going to persist until some method is put in so that
either the guest X server can accept absolute coordinates (a virtual
absolute position pointer device it understands) or there's some for the
host to find out where the guest pointer is. I believe that work is being
done on this now, but we'll have to be patient with it.

SDL probably has the same issue, but I think it can "grab" (hold) the
mouse pointer so that it doesn't run out of the window in the same way it
does with VNC. It does this with fully virtualised machines from what I've
seen.

https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=201220

Robert