> -----Original Message----- > From: Gerd Hoffmann [mailto:kra...@redhat.com] > Sent: 12 October 2017 10:26 > To: Paul Durrant <paul.durr...@citrix.com>; 'Stefano Stabellini' > <sstabell...@kernel.org>; Anthony Perard <anthony.per...@citrix.com> > Cc: qemu-devel@nongnu.org; xen-de...@lists.xenproject.org; Owen Smith > <owen.sm...@citrix.com> > Subject: Re: [Xen-devel] [PATCH 3/3 v4] xenfb: Add [feature|request]-raw- > pointer > > Hi, > > > It's probably OS specific though. I guess the behaviour changed > > because the OS favours absolute pointing devices over relative ones > > and how it has two absolute ones to choose from. How it reconciles > > those, who knows? > > Typically hid emulation calls qemu_input_handler_activate() when the > guest initializes the device, which moves the device to the top of the > priority list. > > Visible effect on a typical guest with ps/2 mouse and usb-tablet is > that qemu switches from relative mode (mouse) to absolute mode (tablet) > when the guest loads the usb hid driver. > > I suspect pvmouse is doing the same thing. So it may simply depend on > guest driver load order whenever pvmouse or usb-tablet is used. > > Simplest fix is probably to only attach the device you plan to use to > the guest. If you can't turn off pvmouse for xen guests then you might > want drop the qemu_input_handler_activate() call, so it behaves simliar > to the ps/2 mouse (is used in case no other pointer device is present).
Avoiding the activate call sounds reasonable and should avoid the behavioural change. Cheers, Paul > > HTH, > Gerd
