Re: [Qemu-devel] [PATCH] usb-hid: Fix 0/0 position for Windows in tablet mode

[Andreas Färber]

Am 25.06.2011 um 14:55 schrieb Jan Kiszka:

> On 2011-06-25 14:37, Andreas Färber wrote:
> > Am 24.06.2011 um 16:27 schrieb Jan Kiszka:
> >
> > > For unknown reasons, Windows drivers (tested with XP and Win7)  
> > > ignore
> > > usb-tablet events that move the pointer to 0/0. So always set bit  
> > > 0 of
> > > the coordinates.
> > >
> > > Signed-off-by: Jan Kiszka <address@hidden>
> > > ---
> > > hw/usb-hid.c |    6 ++++--
> > > 1 files changed, 4 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/hw/usb-hid.c b/hw/usb-hid.c
> > > index d711b5c..2b9a451 100644
> > > --- a/hw/usb-hid.c
> > > +++ b/hw/usb-hid.c
> > > @@ -457,8 +457,10 @@ static void
> > > usb_pointer_event_combine(USBPointerEvent *e, int xyrel,
> > >        e->xdx += x1;
> > >        e->ydy += y1;
> > >    } else {
> > > -        e->xdx = x1;
> > > -        e->ydy = y1;
> > > +        /* Windows drivers do not like the 0/0 position and  
> > > ignore such
> > > +         * events. */
> > > +        e->xdx = x1 | 1;
> > > +        e->ydy = y1 | 1;
> >
> > Doesn't this change mean we can't access any other even pixel either?
>
> Only on 32767x32767 screens (that's the resolution of the tablet).

Well, if it's just a fix for 0/0 I would've expected something like:

e->xdx = x1 ? x1 : 1;
e->ydy = y1 ? y1 : 1;

Andreas