[Qemu-devel] [PATCH] Fix hardware accelerated video to video copy on Cirrus VGA

[Brian Kress <kressb@moose.net>]

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    cirrus_do_copy() in hw/cirrus_vga.c seems to make some incorrect 
assumptions about video
memory layout.  It tries to convert addresses to coordinates assuming 
that one row of data is
(width * depth) bytes long.  The correct way seems to be to use the 
pitch fields in the
CirrusVGAState structure instead.
    Without this patch, I get lots of screen corruption when I try to 
drag a window under X as it's
passing the wrong coordinates to the display surface for the copy.  With 
this patch I can drag a
window with no screen corruption.



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Signed-off-by: Brian Kressb <kressb@moose.net

Index: hw/cirrus_vga.c
===================================================================
--- hw/cirrus_vga.c	(revision 6619)
+++ hw/cirrus_vga.c	(working copy)
@@ -730,10 +730,10 @@
     s->get_resolution((VGAState *)s, &width, &height);
 
     /* extra x, y */
-    sx = (src % (width * depth)) / depth;
-    sy = (src / (width * depth));
-    dx = (dst % (width *depth)) / depth;
-    dy = (dst / (width * depth));
+    sx = (src % ABS(s->cirrus_blt_srcpitch)) / depth;
+    sy = (src / ABS(s->cirrus_blt_srcpitch));
+    dx = (dst % ABS(s->cirrus_blt_dstpitch)) / depth;
+    dy = (dst / ABS(s->cirrus_blt_dstpitch));
 
     /* normalize width */
     w /= depth;