Re: PS/2 emulation - timer?

[Jakob Bohm]

On 2020-11-02 23:25, Peter Maydell wrote:
> On Mon, 2 Nov 2020 at 21:44, Kamil Jońca <kjonca@poczta.onet.pl> wrote:
> > As I wrote earlier there is strange behavior of ps/2 mouse emulation
> > (https://bugs.launchpad.net/qemu/+bug/1618301)
> > I tried to read code
> > (https://github.com/qemu/qemu/blob/master/hw/input/ps2.c) but cannot
> > find anything wrong. The only thing I doubt is time relation issues
> > (ps/2 description mentions about sample rate), but this was rather quick look.
> Not sure. But as a general rule of thumb, you're better off
> going with an absolute-position device (the standard one is
> the USB tablet device) rather than a relative-position one
> like the PS/2 mouse when you're giving the guest an emulated
> pointing device. A relative-position one will always tend to
> get out of sync with the host mouse, and an absolute-position
> one won't.
>
> thanks
> -- PMM
Historically, there were some absolute-position devices that used
the PS/2 port.  These were identified by either a special bit in
the position message, or specific responses to an ID query sent
out the PS/2 port.


Enjoy

Jakob
--
Jakob Bohm, CIO, Partner, WiseMo A/S.  https://www.wisemo.com
Transformervej 29, 2860 Søborg, Denmark.  Direct +45 31 13 16 10
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