diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 3b268b3..75b587e 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -2088,10 +2088,10 @@
 					     "DT compatible string \"$compat\" appears un-documented -- check $dt_path\n" . $herecurr);
 				}
 
-				my $vendor = $compat;
 				my $vendor_path = $dt_path . "vendor-prefixes.txt";
 				next if (! -f $vendor_path);
-				$vendor =~ s/^([a-zA-Z0-9\-]+)\,.*/$1/;
+				next if $compat !~ /^([a-zA-Z0-9\-]+)\,/;
+				my $vendor = $1;
 				`grep -Eq "$vendor" $vendor_path`;
 				if ( $? >> 8 ) {
 					WARN("UNDOCUMENTED_DT_STRING",