Add a helper for the Component Alpha Over case, which breaks the operation

down into an OutReverse and an Add. Turn off the fallback to software
    glyphs when component alpha, now that we expect all (new) drivers to be
    able to support it. Also, make Xephyr fall back in the CA Over case to
    exercise this code. This speeds up my rgb24text and ls -lR in
    gnome-terminal by a factor of 5.

hw/kdrive/ephyr/ephyr_draw.c

@@ -226,6 +226,12 @@ static Bool
 ephyrCheckComposite(int op, PicturePtr pSrcPicture, PicturePtr pMaskPicture,
 		    PicturePtr pDstPicture)
 {
+    /* Exercise the component alpha helper, so fail on this case like a normal
+     * driver
+     */
+    if (pMaskPicture && pMaskPicture->componentAlpha && op == PictOpOver)
+	return FALSE;
+
     return TRUE;
 }