xserver: Branch 'master'

[Keith Packard]

 fb/fbbits.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

New commits:
commit 3e56efcfb63677cd8574e1e435e61d96f79ea536
Author: Keith Packard <keithp at keithp.com>
Date:   Fri Aug 20 10:01:48 2010 -0700

    fb: make isClipped always reject negative coordinates (bug 11503)
    
    A window with either dimension > 32767 can be positioned such that
    coordinates > 32767 are visible on the screen. Attempts to draw to
    those pixels will generate coordinates wrapped around to negative
    values.
    
    The optimized clipping macro, 'isClipped', in fbbits.h, computes
    clipping in window space rather than screen space using int16 values,
    and so it too has coordinates wrapped around to negative values and
    hence ends up accepting the wrapped drawing coordinates.
    
    Two possible fixes for this problem
    
     1) Detect wrapped region coordinates and clip those to 32767.
     2) Detect negative incoming coordinates and reject those
    
    This patch takes the second approach as it is much shorter, simply
    detecting when either X or Y incoming coordinate is negative, which
    can never be 'within' any drawable.
    
    Signed-off-by: Keith Packard <keithp at keithp.com>
    Reviewed-by: Adam Jackson <ajax at redhat.com>

diff --git a/fb/fbbits.h b/fb/fbbits.h
index 8bf1a02..2dec84b 100644
--- a/fb/fbbits.h
+++ b/fb/fbbits.h
@@ -25,7 +25,7 @@
  * underlying datatypes instead of masks
  */
 
-#define isClipped(c,ul,lr)  ((((c) - (ul)) | ((lr) - (c))) & 0x80008000)
+#define isClipped(c,ul,lr)  (((c) | ((c) - (ul)) | ((lr) - (c))) & 0x80008000)
 
 #ifdef HAVE_DIX_CONFIG_H
 #include <dix-config.h>