[PATCH] dix: make sure the mask is set for emulated scroll events

[Peter Hutterer]

If a device has smooth scrolling axes, but submits scroll button events, we
convert those to motion events and update the valuators. For legacy button
events, the valuator mask is likely unset though, causing
add_to_scroll_valuator() to return early, leaving us with an empty mask.
That again skipped the rest of the code and no events were generated.

Fix it by making sure that the scroll valuator in the mask is at least
initialized to 0.

Broke evdev wheel emulation, introduced by
54476b5e4461ff523e935961affabcf0de12c556.

Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
---
 dix/getevents.c |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/dix/getevents.c b/dix/getevents.c
index 27c2e04..b3bb162 100644
--- a/dix/getevents.c
+++ b/dix/getevents.c
@@ -1625,6 +1625,8 @@ GetPointerEvents(InternalEvent *events, DeviceIntPtr pDev, int type,
 
         if (adj != 0.0 && axis != -1) {
             adj *= pDev->valuator->axes[axis].scroll.increment;
+            if (!valuator_mask_isset(&mask, axis))
+                valuator_mask_set(&mask, axis, 0);
             add_to_scroll_valuator(pDev, &mask, axis, adj);
             type = MotionNotify;
             buttons = 0;
-- 
1.7.10.4