[PATCH 1/2] mi: fix cursor warping screens

[Peter Hutterer]

On Wed, Aug 05, 2009 at 09:18:55PM +0300, y at mgw-mx09.nokia.com wrote:
> From: Tiago Vignatti <tiago.vignatti at nokia.com>
> 
> The server was processing ET_RawMotion type when the cursor was wrapping to
> another screen and getting wrong valuator values. This fix such issue
> considering only ET_Motion, ET_KeyPress, ET_KeyRelease, ET_ButtonPress and
> ET_ButtonRelease types when the cursor detects a new screen.
> 
> Signed-off-by: Tiago Vignatti <tiago.vignatti at nokia.com>
> ---
>  mi/mieq.c |   24 ++++++++++++++++--------
>  1 files changed, 16 insertions(+), 8 deletions(-)
> 
> diff --git a/mi/mieq.c b/mi/mieq.c
> index 6ec2dba..b52ed84 100644
> --- a/mi/mieq.c
> +++ b/mi/mieq.c
> @@ -367,14 +367,22 @@ mieqProcessDeviceEvent(DeviceIntPtr dev,
>      /* Custom event handler */
>      handler = miEventQueue.handlers[event->any.type];
>  
> -    if (dev && screen && screen != DequeueScreen(dev) && !handler) {
> -        /* Assumption - screen switching can only occur on motion events. */
> -        DequeueScreen(dev) = screen;
> -        x = event->device.root_x;
> -        y = event->device.root_y;
> -        NewCurrentScreen (dev, DequeueScreen(dev), x, y);
> -    }
> -    else {
> +    switch (event->any.type) {
> +        /* Catch events that include valuator information and check if they
> +         * are changing the screen */
> +        case ET_Motion:
> +        case ET_KeyPress:
> +        case ET_KeyRelease:
> +        case ET_ButtonPress:
> +        case ET_ButtonRelease:
> +            if (dev && screen && screen != DequeueScreen(dev) && !handler) {
> +                DequeueScreen(dev) = screen;
> +                x = event->device.root_x;
> +                y = event->device.root_y;
> +                NewCurrentScreen (dev, DequeueScreen(dev), x, y);
> +                break;
> +            }

please always add a comment when an intentional fallthrough is used in a
switch statement.
anyway, having a return instead of a break after the dequeue stuff means we
wouldn't need the large default block. 

This whole thing looks odd though. If the screen switch happens on a button
or key release event, the event isn't processed and we'd end up with a stuck
button or key.
I think the return is only supposed to happen on a ET_Motion, with the other
events falling through to the default case.

> +        default:
>          master = CopyGetMasterEvent(dev, event, &mevent);
>  
>          if (master)
> -- 
> 1.5.6.3

Cheers,
  Peter