EFI disk probing problem

[bibo,mao]

hi,
 My hard disk is MBR partition type, there is FAT partition in my logical
partition, bootloader grub.efi is in this partition. When grub efi 
bootloader starts up, it cannot probe my hard disk. It is because that
parent device_path of current logical partition is extended partition, but
not my hard disk's device path.
  Here I wrote one patch to solve this problem, I discarded the device
whose type is not GRUB_EFI_MEDIA_DEVICE_PATH_TYPE, added devices whose type
is GRUB_EFI_MESSAGING_DEVICE_PATH_TYPE  as hard-disk or cdrom disk.
  Any suggestion is welcome:) I sent email to grub mailing list, but there
is no response, I do not know why.

thanks
bibo,mao

--- grub-1.94.org/disk/efi/efidisk.c    2006-05-01 05:09:37.000000000 +0800
+++ grub-1.94/disk/efi/efidisk.c        2006-07-26 13:00:09.000000000 +0800
@@ -87,6 +87,51 @@ find_last_device_path (const grub_efi_de
  return p;
}

+static int compare_ancestor_path(const grub_efi_device_path_t *parent,
+                const grub_efi_device_path_t *dp2)
+{
+       if (! parent || ! dp2)
+               /* Return non-zero.  */
+               return 1;
+
+       while (1){
+               grub_efi_uint8_t type1, type2;
+               grub_efi_uint8_t subtype1, subtype2;
+               grub_efi_uint16_t len1, len2;
+               int ret;
+
+               if (GRUB_EFI_END_ENTIRE_DEVICE_PATH(parent))
+                               break;
+
+               type1 = GRUB_EFI_DEVICE_PATH_TYPE (parent);
+               type2 = GRUB_EFI_DEVICE_PATH_TYPE (dp2);
+
+               if (type1 != type2)
+                               return (int) type2 - (int) type1;
+
+               subtype1 = GRUB_EFI_DEVICE_PATH_SUBTYPE (parent);
+               subtype2 = GRUB_EFI_DEVICE_PATH_SUBTYPE (dp2);
+
+               if (subtype1 != subtype2)
+                               return (int) subtype1 - (int) subtype2;
+
+               len1 = GRUB_EFI_DEVICE_PATH_LENGTH (parent);
+               len2 = GRUB_EFI_DEVICE_PATH_LENGTH (dp2);
+
+               if (len1 != len2)
+                               return (int) len1 - (int) len2;
+
+               ret = grub_memcmp (parent, dp2, len1);
+               if (ret != 0)
+                               return ret;
+
+               parent = (grub_efi_device_path_t *) ((char *) parent + len1);
+               dp2 = (grub_efi_device_path_t *) ((char *) dp2 + len2);
+       }
+
+       return 0;
+}
+
/* Compare device paths.  */
static int
compare_device_paths (const grub_efi_device_path_t *dp1,
@@ -301,109 +346,34 @@ add_device (struct grub_efidisk_data **d
}

/* Name the devices.  */
-static void
-name_devices (struct grub_efidisk_data *devices)
-{
-  struct grub_efidisk_data *d;
-  
-  /* First, identify devices by media device paths.  */
-  for (d = devices; d; d = d->next)
-    {
-      grub_efi_device_path_t *dp;
+static void name_devices (struct grub_efidisk_data *devices){
+       struct grub_efidisk_data *d;

-      dp = d->last_device_path;
-      if (! dp)
-       continue;
-      
-      if (GRUB_EFI_DEVICE_PATH_TYPE (dp) == GRUB_EFI_MEDIA_DEVICE_PATH_TYPE)
-       {
-         int is_hard_drive = 0;
-	  
-	  switch (GRUB_EFI_DEVICE_PATH_SUBTYPE (dp))
-           {
-           case GRUB_EFI_HARD_DRIVE_DEVICE_PATH_SUBTYPE:
-             is_hard_drive = 1;
-             /* Fall through by intention.  */
-           case GRUB_EFI_CDROM_DEVICE_PATH_SUBTYPE:
-             {
-               struct grub_efidisk_data *parent;
-
-               parent = find_parent_device (devices, d);
-               if (parent)
-                 {
-                   if (is_hard_drive)
-                     {
-#if 0
-                       grub_printf ("adding a hard drive by a partition: ");
-                       grub_print_device_path (parent->device_path);
-#endif
-                       add_device (&hd_devices, parent);
-                     }
-                   else
-                     {
-#if 0
-                       grub_printf ("adding a cdrom by a partition: ");
-                       grub_print_device_path (parent->device_path);
-#endif
-                       add_device (&cd_devices, parent);
-                     }
-		    
-		    /* Mark the parent as used.  */
-                   parent->last_device_path = 0;
-                 }
-             }
-             /* Mark itself as used.  */
-             d->last_device_path = 0;
-             break;
-
-           default:
-             /* For now, ignore the others.  */
-             break;
-           }
-       }
-    }
-
-  /* Let's see what can be added more.  */
-  for (d = devices; d; d = d->next)
-    {
-      grub_efi_device_path_t *dp;
-      grub_efi_block_io_media_t *m;
-      
-      dp = d->last_device_path;
-      if (! dp)
-       continue;
-
-      m = d->block_io->media;
-      if (m->logical_partition)
-       {
-         /* Only one partition in a non-media device. Assume that this
-            is a floppy drive.  */
-#if 0
-         grub_printf ("adding a floppy by guessing: ");
-         grub_print_device_path (d->device_path);
-#endif
-         add_device (&fd_devices, d);
-       }
-      else if (m->read_only && m->block_size > GRUB_DISK_SECTOR_SIZE)
-       {
-         /* This check is too heuristic, but assume that this is a
-            CDROM drive.  */
-#if 0
-         grub_printf ("adding a cdrom by guessing: ");
-         grub_print_device_path (d->device_path);
-#endif
-         add_device (&cd_devices, d);
-       }
-      else
-       {
-         /* The default is a hard drive.  */
-#if 0
-         grub_printf ("adding a hard drive by guessing: ");
-         grub_print_device_path (d->device_path);
-#endif
-         add_device (&hd_devices, d);
+       /* Let's see what can be added more.  */
+       for (d = devices; d; d = d->next){
+               grub_efi_device_path_t *dp;
+               grub_efi_block_io_media_t *m;
+
+               dp = d->last_device_path;
+               if (! dp)
+                               continue;
+
+               m = d->block_io->media;
+
+               if (GRUB_EFI_DEVICE_PATH_TYPE(dp) == 
GRUB_EFI_MESSAGING_DEVICE_PATH_TYPE){
+                       if (m->read_only && m->block_size > 
GRUB_DISK_SECTOR_SIZE){
+                               grub_printf("adding a cd by guessing\n");
+                               add_device (&cd_devices, d);
+                       } else{
+                               grub_printf("adding a hd by guessing\n");
+                               add_device (&hd_devices, d);
+                       }
+               }
+               if (GRUB_EFI_DEVICE_PATH_TYPE(dp) == 
GRUB_EFI_ACPI_DEVICE_PATH_TYPE){
+                               grub_printf ("adding a floppy by guessing\n");
+                               add_device (&fd_devices, d);
+               }
        }
-    }
}

static void
@@ -751,7 +721,7 @@ grub_efidisk_get_device_name (grub_efi_h
              struct grub_efidisk_data *d;
	      
	      d = disk->data;
-             if (compare_device_paths (d->device_path, dup_dp) == 0)
+             if (compare_ancestor_path(d->device_path, dp) == 0)
                {
                  parent = disk;
                  return 1;
@@ -776,20 +746,7 @@ grub_efidisk_get_device_name (grub_efi_h
          return 0;
        }

-      /* It is necessary to duplicate the device path so that GRUB
-        can overwrite it.  */
-      dup_dp = duplicate_device_path (dp);
-      if (! dup_dp)
-       return 0;
-
-      dup_ldp = find_last_device_path (dup_dp);
-      dup_ldp->type = GRUB_EFI_END_DEVICE_PATH_TYPE;
-      dup_ldp->subtype = GRUB_EFI_END_ENTIRE_DEVICE_PATH_SUBTYPE;
-      dup_ldp->length[0] = sizeof (*dup_ldp);
-      dup_ldp->length[1] = 0;
-
      grub_efidisk_iterate (find_parent_disk);
-      grub_free (dup_dp);

      if (! parent)
        return 0;