Re: [Qemu-devel] [PATCH v2] usb-hid: Fix 0/0 position for Windows in tablet mode

[Andreas Färber]

Am 12.07.2011 um 09:47 schrieb Jan Kiszka:

> On 2011-07-04 20:15, andrzej zaborowski wrote:
> > On 26 June 2011 11:11, Jan Kiszka <address@hidden> wrote:
> > > On 2011-06-25 15:10, Andreas Färber wrote:
> > > > 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;
> > >
> > > Works as well, my version is a little bit simpler. But I don't mind,
> > > will post whatever is preferred to fix this.
> >
> > Would it be enough to just do this for x or y, not both?
>
> Yes, looks like. Is this one better?

To me it looks better, yes.

Thanks,
Andreas

> ----------8<---------
>
> From: Jan Kiszka <address@hidden>
>
> For unknown reasons, Windows drivers (tested with XP and Win7) ignore
> usb-tablet events that move the pointer to 0/0. So always report 0/0  
> as
> 1/0.
>
> Signed-off-by: Jan Kiszka <address@hidden>
> ---
> hw/usb-hid.c |    5 +++++
> 1 files changed, 5 insertions(+), 0 deletions(-)
>
> diff --git a/hw/usb-hid.c b/hw/usb-hid.c
> index d711b5c..faf91c4 100644
> --- a/hw/usb-hid.c
> +++ b/hw/usb-hid.c
> @@ -459,6 +459,11 @@ static void  
> usb_pointer_event_combine(USBPointerEvent *e, int xyrel,
>     } else {
>         e->xdx = x1;
>         e->ydy = y1;
> +        /* Windows drivers do not like the 0/0 position and ignore  
> such
> +         * events. */
> +        if (!(x1 | y1)) {
> +            x1 = 1;
> +        }
>     }
>     e->dz += z1;
> }
> --
> 1.7.3.4