diff -r 2629f0b99e8d -r a9de774c9d02 src/dev/i8254xGBe.cc
--- a/src/dev/i8254xGBe.cc	Mon Feb 20 08:11:14 2012 -0800
+++ b/src/dev/i8254xGBe.cc	Sat Mar 03 15:07:36 2012 -0600
@@ -1923,12 +1923,12 @@
         igbe->anBegin("TXS", "Desc Writeback");
         DPRINTF(EthernetDesc, "WTHRESH == 0, writing back descriptor\n");
         writeback(0);
-    } else if (igbe->regs.txdctl.gran() && igbe->regs.txdctl.wthresh() >=
+    } else if (!igbe->regs.txdctl.gran() && igbe->regs.txdctl.wthresh() <=
                descInBlock(usedCache.size())) {
         DPRINTF(EthernetDesc, "used > WTHRESH, writing back descriptor\n");
         igbe->anBegin("TXS", "Desc Writeback");
         writeback((igbe->cacheBlockSize()-1)>>4);
-    } else if (igbe->regs.txdctl.wthresh() >= usedCache.size()) {
+    } else if (igbe->regs.txdctl.wthresh() <= usedCache.size()) {
         DPRINTF(EthernetDesc, "used > WTHRESH, writing back descriptor\n");
         igbe->anBegin("TXS", "Desc Writeback");
         writeback((igbe->cacheBlockSize()-1)>>4);