diff --git a/support/scripts/setlocalversion b/support/scripts/setlocalversion
index a6edd7194..adeeb781e 100755
--- a/support/scripts/setlocalversion
+++ b/support/scripts/setlocalversion
@@ -1,5 +1,13 @@
 #!/bin/sh
-# Print additional version information for non-release trees.
+#
+# This scripts adds local version information from the version
+# control systems git, mercurial (hg) and subversion (svn).
+#
+# If something goes wrong, send a mail the kernel build mailinglist
+# (see MAINTAINERS) and CC Nico Schottelius
+# <nico-linuxsetlocalversion -at- schottelius.org>.
+#
+#
 
 usage() {
 	echo "Usage: $0 [srctree]" >&2
@@ -10,10 +18,17 @@ cd "${1:-.}" || usage
 
 # Check for git and a git repo.
 if head=`git rev-parse --verify --short HEAD 2>/dev/null`; then
-	# Do we have an untagged version?
-	if git name-rev --tags HEAD | grep -E '^HEAD[[:space:]]+(.*~[0-9]*|undefined)$' > /dev/null; then
-		if tag=`git describe 2>/dev/null`; then
-			echo $tag | awk -F- '{printf("-%05d-%s", $(NF-1),$(NF))}'
+
+	# If we are at a tagged commit (like "v2.6.30-rc6"), we ignore it,
+	# because this version is defined in the top level Makefile.
+	if [ -z "`git describe --exact-match 2>/dev/null`" ]; then
+
+		# If we are past a tagged commit (like "v2.6.30-rc5-302-g72357d5"),
+		# we pretty print it.
+		if atag="`git describe 2>/dev/null`"; then
+			echo "$atag" | awk -F- '{printf("-%05d-%s", $(NF-1),$(NF))}'
+
+		# If we don't have a tag at all we print -g{commitish}.
 		else
 			printf '%s%s' -g $head
 		fi
@@ -24,8 +39,10 @@ if head=`git rev-parse --verify --short HEAD 2>/dev/null`; then
 	        printf -- '-svn%s' "`git svn find-rev $head`"
 	fi
 
-	# Are there uncommitted changes?
-	git update-index --refresh --unmerged > /dev/null
+	# Update index only on r/w media
+	[ -w . ] && git update-index --refresh --unmerged > /dev/null
+
+	# Check for uncommitted changes
 	if git diff-index --name-only HEAD | grep -v "^scripts/package" \
 	    | read dummy; then
 		printf '%s' -dirty
@@ -58,14 +75,7 @@ fi
 # Check for svn and a svn repo.
 if rev=`LC_ALL=C svn info 2>/dev/null | grep '^Last Changed Rev'`; then
 	rev=`echo $rev | awk '{print $NF}'`
-	changes=`LC_ALL=C svn status 2>/dev/null | grep '^[AMD]' | wc -l`
-
-	# Are there uncommitted changes?
-	if [ $changes != 0 ]; then
-		printf -- '-svn%s%s' "$rev" -dirty
-	else
-		printf -- '-svn%s' "$rev"
-	fi
+	printf -- '-svn%s' "$rev"
 
 	# All done with svn
 	exit