i810 patch

[Patrick Welche <prlw1%cam.ac.uk@localhost>]

We seem to have

--- /tmp/foo/src/legacy/i810/i810_dri.c 2014-09-08 08:53:32.000000000 +0100
+++ /usr/xsrc/external/mit/xf86-video-intel/dist/src/legacy/i810/i810_dri.c     2014-11-06 16:32:19.000000000 +0000
@@ -1104,10 +1104,17 @@
            while ((pboxNext >= pbox) && (pboxBase->y1 == pboxNext->y1))
               pboxNext--;
            pboxTmp = pboxNext + 1;
-           pptTmp = pptSrc + (pboxTmp - pbox);
-           while (pboxTmp <= pboxBase) {
-              *pboxNew1++ = *pboxTmp++;
-              *pptNew1++ = *pptTmp++;
+           if (pptSrc == &ptOldOrg) {
+               if (pboxTmp <= pboxBase) {
+                 *pboxNew1++ = *pboxTmp;
+                 *pptNew1++ = *pptSrc;
+               }
+           } else {
+              pptTmp = pptSrc + (pboxTmp - pbox);
+              while (pboxTmp <= pboxBase) {
+                 *pboxNew1++ = *pboxTmp++;
+                 *pptNew1++ = *pptTmp++;
+              }
            }
            pboxBase = pboxNext;
         }

in our tree, but I can't seem to find a commit message explaining what
it is for... Any ideas? Should it go upstream?

Cheers,

Patrick