[PATCH v1 1/2] Skip diskfilter on powerpc CDs

[Robbie Harwood]

Prior to this change, on ppc64le with part_msdos and the mdraid* modules
enabled, we see:

    disk/diskfilter.c:191: scanning ieee1275/cdrom
    kern/disk.c:196: Opening `ieee1275/cdrom'...
    disk/ieee1275/ofdisk.c:477: Opening `cdrom'.
    disk/ieee1275/ofdisk.c:502: MAX_RETRIES set to 20
    kern/disk.c:288: Opening `ieee1275/cdrom' succeeded.
    disk/diskfilter.c:136: Scanning for DISKFILTER devices on disk 
ieee1275/cdrom
    partmap/msdos.c:184: partition 0: flag 0x80, type 0x96, start 0x0, len
    0x6a5d70
    disk/diskfilter.c:136: Scanning for DISKFILTER devices on disk 
ieee1275/cdrom
    SCSI-DISK: Access beyond end of device !
    SCSI-DISK: Access beyond end of device !
    SCSI-DISK: Access beyond end of device !
    SCSI-DISK: Access beyond end of device !
    SCSI-DISK: Access beyond end of device !
    disk/ieee1275/ofdisk.c:578: MAX_RETRIES set to 20

These latter two lines repeat many times, eventually ending in:

    kern/disk.c:388: ieee1275/cdrom read failed
    error: ../../grub-core/disk/ieee1275/ofdisk.c:608:failure reading sector
    0x1a9720 from `ieee1275/cdrom'.

and the system drops to a "grub>" prompt.

The firmware and the iso image appear to diagree on the blocksize (512
vs. 2048), and the diskfilter RAID probing is too much for it.  We won't
be seeing RAID on bootable CDs, so just turn it off.

Signed-off-by: Robbie Harwood <rharwood@redhat.com>
---
 grub-core/disk/diskfilter.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/grub-core/disk/diskfilter.c b/grub-core/disk/diskfilter.c
index 1c568927b8..35f45cb95e 100644
--- a/grub-core/disk/diskfilter.c
+++ b/grub-core/disk/diskfilter.c
@@ -133,6 +133,11 @@ scan_disk_partition_iter (grub_disk_t disk, 
grub_partition_t p, void *data)
   struct grub_diskfilter_pv_id id;
   grub_diskfilter_t diskfilter;
 
+#ifdef __powerpc__
+  if (!grub_strcmp (name, "ieee1275/cdrom"))
+    return 0;
+#endif
+
   grub_dprintf ("diskfilter", "Scanning for DISKFILTER devices on disk %s\n",
                name);
 #ifdef GRUB_UTIL
-- 
2.39.0