diff --git a/man2/s390_pci_mmio_write.2 b/man2/s390_pci_mmio_write.2
index a9088c25f..9bee6a21f 100644
--- a/man2/s390_pci_mmio_write.2
+++ b/man2/s390_pci_mmio_write.2
@@ -30,10 +30,10 @@ MMIO memory page
 .nf
 .B #include <asm/unistd.h>
 .PP
-.BI "int s390_pci_mmio_write(unsigned long " mmio_addr ","
-.BI "                        void *" user_buffer ", size_t " length ");"
-.BI "int s390_pci_mmio_read(unsigned long " mmio_addr ","
-.BI "                        void *" user_buffer ", size_t " length ");"
+.BI "int s390_pci_mmio_write(unsigned long " mmio_addr ,
+.BI "                       const void *" user_buffer ", size_t " length );
+.BI "int s390_pci_mmio_read(unsigned long " mmio_addr ,
+.BI "                       void *" user_buffer ", size_t " length );
 .fi
 .PP
 .IR Note :