[PATCH RFC xserver] wayland: clear resource for pixmap on unrealize

[Olivier Fourdan]

On cursor unrealize, the associated pixmap is destroyed, make sure we
clear the pointer from the private resource and check for the value
being non-null when setting or destroying the cursor.

Signed-off-by: Olivier Fourdan <ofourdan at redhat.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=96246
---
 Hi,

 Sending this patch as an RFC, I am not sure if it cures just the effects
 of a more complex issue, or if it's the right fix for the bug mentioned
 above.

 For Fedora we have quite of few similar reports that appeared after we
 switched to 1.18.3, and the most likely related change is commit 1815540

     xwayland: Clear pending cursor frame callbacks on pointer enter

 But I am not entirely sure how such a change can cause this issue.

 Anyway, if you have a better understanding of the problem, free free to
 chime in! :)

 Cheers,
 Olivier 

 hw/xwayland/xwayland-cursor.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/hw/xwayland/xwayland-cursor.c b/hw/xwayland/xwayland-cursor.c
index 76729db..44fadf4 100644
--- a/hw/xwayland/xwayland-cursor.c
+++ b/hw/xwayland/xwayland-cursor.c
@@ -78,6 +78,10 @@ xwl_unrealize_cursor(DeviceIntPtr device, ScreenPtr screen, CursorPtr cursor)
     PixmapPtr pixmap;
 
     pixmap = dixGetPrivate(&cursor->devPrivates, &xwl_cursor_private_key);
+    if (!pixmap)
+        return TRUE;
+
+    dixSetPrivate(&cursor->devPrivates, &xwl_cursor_private_key, NULL);
 
     return xwl_shm_destroy_pixmap(pixmap);
 }
@@ -122,6 +126,9 @@ xwl_seat_set_cursor(struct xwl_seat *xwl_seat)
 
     cursor = xwl_seat->x_cursor;
     pixmap = dixGetPrivate(&cursor->devPrivates, &xwl_cursor_private_key);
+    if (!pixmap)
+        return;
+
     stride = cursor->bits->width * 4;
     if (cursor->bits->argb)
         memcpy(pixmap->devPrivate.ptr,
-- 
2.7.4