Re: [Xen-devel] Xen 3.4.x and request-abs-pointer

[John Haxby <john.haxby@xxxxxxxxxx>]

On 05/07/10 17:41, Stefano Stabellini wrote:
> On Mon, 5 Jul 2010, John Haxby wrote:
>    
> > On 05/07/10 16:45, Stefano Stabellini wrote:
> >      
> > > That patch was recently reverted because it was the wrong fix:
> > >
> > >
> > >        
> > Rats.
> >
> > Back to my previous attempt then which seemed a little less elegant: the
> > idea was that I would initially register the pointer as relative but
> > check in the first call to xenfb_mouse_event() and if I had guessed
> > wrong, remove the existing mouse handler and add a new one with
> > registered as absolute.  If the mouse turns out to be absolute, we miss
> > the very first pointer event but this doesn't seem to be much of an
> > issue because everything will be sorted out on the next mouse event (the
> > various pieces of code that are interested in whether or not the mouse
> > is enabled seem to be OK about switching from relative to absolute).
> >
> > Before I commit a patch to electrons are the any obvious flaws in that
> > approach?
> >
> >      
> I think that solution is not very elegant besides it doesn't fix the
> basic issue that is on qemu side.
>    
Yeah, you're right.  It sucks.  That's what comes of writing down 
something random just before you go home for the day.
> The proper fix  would be to add a new hook in qemu like suggested
> in the previous email:
>
>    
> > In order to do that properly we need a new hook in qemu xen_backend: we
> > should probably rename the current connect hook to initialise and create
> > a new connect hook that would be implemented by xenfb to read
> > request-abs-pointer.
> >      
> Basically we need a new callback from xen_backend.c on
> XenbusStateConnected.
> The current "connect" hook can be called on both XenbusStateInitialised
> and XenbusStateConnected so it doesn't suit our needs.
> I suggest to rename the current "connect" hook to "initialised", and
> create a new "connect" hook that is called only on XenbusStateConnected.
> In the xenfb.c implementation of the new connect hook you can read
> request-abs-pointer and be sure that it was previously set by the guest.
>
>    
Sounds reasonable.

jch


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