diff --git a/var/spack/repos/builtin/packages/dedisp/package.py b/var/spack/repos/builtin/packages/dedisp/package.py
index 557fd943c41..7634ba306c0 100644
--- a/var/spack/repos/builtin/packages/dedisp/package.py
+++ b/var/spack/repos/builtin/packages/dedisp/package.py
@@ -36,10 +36,10 @@ def edit(self, spec, prefix):
         makefile.filter(r"^\s*INSTALL_DIR\s*\?=.*", "INSTALL_DIR ?= " + prefix)
 
     @run_before("install")
-    def preinstall(self, spec, prefix):
+    def preinstall(self):
         # The $PREFIX/dedisp/include and $PREFIX/dedisp/lib directories don't seem
         # to be created automatically by the software's Makefile so manually create them
-        libdir = join_path(prefix, "lib")
-        incdir = join_path(prefix, "include")
+        libdir = join_path(self.prefix, "lib")
+        incdir = join_path(self.prefix, "include")
         mkdirp(libdir)
         mkdirp(incdir)