diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 9fcaac8bc4f6..5e3a906cc089 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -51,7 +51,7 @@ struct resource {
 
 #define IORESOURCE_EXCLUSIVE	0x08000000	/* Userland may not map this resource */
 #define IORESOURCE_DISABLED	0x10000000
-#define IORESOURCE_UNSET	0x20000000
+#define IORESOURCE_UNSET	0x20000000	/* No address assigned yet */
 #define IORESOURCE_AUTO		0x40000000
 #define IORESOURCE_BUSY		0x80000000	/* Driver has marked this resource busy */
 
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 185b6d300ebc..5e2cf6f342f8 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -719,10 +719,15 @@ char *resource_string(char *buf, char *end, struct resource *res,
 		specp = &mem_spec;
 		decode = 0;
 	}
-	p = number(p, pend, res->start, *specp);
-	if (res->start != res->end) {
-		*p++ = '-';
-		p = number(p, pend, res->end, *specp);
+	if (decode && res->flags & IORESOURCE_UNSET) {
+		p = string(p, pend, "size ", str_spec);
+		p = number(p, pend, resource_size(res), *specp);
+	} else {
+		p = number(p, pend, res->start, *specp);
+		if (res->start != res->end) {
+			*p++ = '-';
+			p = number(p, pend, res->end, *specp);
+		}
 	}
 	if (decode) {
 		if (res->flags & IORESOURCE_MEM_64)