- Don't try to upload 0 byte-per-pixel (PICT_a1) data using

RADEONHostDataBlit.
- Disable the shortcut for switching from 3d to 3d in radeon_exa.c. It
    appears that we do need the cache flush here, thought it's not clear
    why. Disable the 2d to 2d shortcut while here, since I'm unsure of what
    we're doing. Exposed by the following bit:
- Bug #4485: Add a new routine, exaGlyphs, to handle font drawing. Glyphs
    were being accumulated in from non-migratable scratch pixmaps, causing
    the destination pixmap to move towards screen but the migration
    necessary for source never to happen, leading to abysmal performance.
    Instead, copy the scratch glyph data into a real pixmap first, then
    composite from that into the destination, allowing for migration. time
    ls -lR from programs/Xserver showed 26.9% (+/- 6.3%) decrease in wall
    time (n=3).
- Create exaDrawableUse* wrapping exaPixmapUse*, but which are aware of
    windows needing backing store. Makes migration code prettier, and
    ensures that composited windows will be migrated as normal when we turn
    off cw for EXA. (issue brought up by keithp)

exa/exa_priv.h

@@ -70,6 +70,7 @@ typedef struct {
     CopyWindowProcPtr 		 SavedCopyWindow;
 #ifdef RENDER
     CompositeProcPtr             SavedComposite;
+    GlyphsProcPtr                SavedGlyphs;
 #endif
     EnableDisableFBAccessProcPtr SavedEnableDisableFBAccess;
     Bool			 wrappedEnableDisableFB;
@@ -241,6 +242,12 @@ void
 exaEnableDisableFBAccess (int index, Bool enable);
 
 /* exa.c */
+void
+exaDrawableUseScreen(DrawablePtr pDrawable);
+
+void
+exaDrawableUseMemory(DrawablePtr pDrawable);
+
 void
 exaPixmapUseScreen (PixmapPtr pPixmap);
 
@@ -299,4 +306,15 @@ exaComposite(CARD8	op,
 	     CARD16	width,
 	     CARD16	height);
 
+void
+exaGlyphs (CARD8	op,
+	  PicturePtr	pSrc,
+	  PicturePtr	pDst,
+	  PictFormatPtr	maskFormat,
+	  INT16		xSrc,
+	  INT16		ySrc,
+	  int		nlist,
+	  GlyphListPtr	list,
+	  GlyphPtr	*glyphs);
+
 #endif /* EXAPRIV_H */