static void port_cleanup(struct smi_info *info)
 {
        unsigned int addr = info->io.addr_data;
-       int          mapsize;
+       int          idx;
 
        if (addr) {
-               mapsize = ((info->io_size * info->io.regspacing)
-                          - (info->io.regspacing - info->io.regsize));
-
-               release_region (addr, mapsize);
+               for (idx = 0; idx < info->io_size; idx++) {
+                       release_region(addr + idx * info->io.regspacing,
+                                      info->io.regsize);
+               }
        }
 }
 
 static int port_setup(struct smi_info *info)
 {
        unsigned int addr = info->io.addr_data;
-       int          mapsize;
+       int          idx;
 
        if (!addr)
                return -ENODEV;
                return -EINVAL;
        }
 
-       /* Calculate the total amount of memory to claim.  This is an
-        * unusual looking calculation, but it avoids claiming any
-        * more memory than it has to.  It will claim everything
-        * between the first address to the end of the last full
-        * register. */
-       mapsize = ((info->io_size * info->io.regspacing)
-                  - (info->io.regspacing - info->io.regsize));
-
-       if (request_region(addr, mapsize, DEVICE_NAME) == NULL)
-               return -EIO;
+       /* Some BIOSes reserve disjoint I/O regions in their ACPI
+        * tables.  This causes problems when trying to register the
+        * entire I/O region.  Therefore we must register each I/O
+        * port separately.
+        */
+       for (idx = 0; idx < info->io_size; idx++) {
+               if (request_region(addr + idx * info->io.regspacing,
+                                  info->io.regsize, DEVICE_NAME) == NULL) {
+                       /* Undo allocations */
+                       while (idx--) {
+                               release_region(addr + idx * info->io.regspacing,
+                                              info->io.regsize);
+                       }
+                       return -EIO;
+               }
+       }
        return 0;
 }