--- zzzz-none-000/linux-3.10.107/arch/powerpc/kernel/io.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/arch/powerpc/kernel/io.c	2021-02-04 17:41:59.000000000 +0000
@@ -25,6 +25,9 @@
 #include <asm/firmware.h>
 #include <asm/bug.h>
 
+/* See definition in io.h */
+bool isa_io_special;
+
 void _insb(const volatile u8 __iomem *port, void *buf, long count)
 {
 	u8 *tbuf = buf;