IMSM (Intel Matrix Storage Manager) device is not detected by 6.6.x/6.7.x but works in 5.19.17

[Aleksey Midenkov]

In 6.x.x /dev/md/imsm0 does not appear at boot.
The only difference I see in dmesg which seems to be relevant:

  block device autoloading is deprecated and will be removed.

Printed in 5.x.x, but not in 6.x.x.

/proc/mdstat in 5.x.x:

Personalities : [raid0] [linear] [multipath] [raid1] [raid6] [raid5]
[raid4] [raid10]
md126 : active raid0 sdb[1] sda[0]
     937698304 blocks super external:/md127/0 128k chunks

md127 : inactive sdb[1](S) sda[0](S)
     4784 blocks super external:imsm

/proc/mdstat in 6.x.x:

Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5]
[raid4] [raid10]
unused devices: <none>

Kernel config is the same regarding MD and RAID. Trying to manually
assemble RAID in 6.x.x leads to:

mdadm: looking for devices for /dev/md0
mdadm: No OROM/EFI properties for /dev/sda
mdadm: no RAID superblock on /dev/sda
mdadm: /dev/sda has no superblock - assembly aborted

While superblock is correctly displayed by 6.x.x as well:

/dev/sda:
         Magic : Intel Raid ISM Cfg Sig.
       Version : 1.0.00
   Orig Family : 38d93728
        Family : 38d93728
    Generation : 0000018b
 Creation Time : Unknown
    Attributes : All supported
          UUID : b762ef98:7900e4ea:f6395076:47a40d15
      Checksum : 4c2193cc correct
   MPB Sectors : 1
         Disks : 2
  RAID Devices : 1

 Disk01 Serial : YG952401WA480BGN
         State : active
            Id : 00000000
   Usable Size : 937698304 (447.13 GiB 480.10 GB)

[Vortex]:
      Subarray : 0
          UUID : b41d5d94:b2438127:629eca5c:4a65945a
    RAID Level : 0
       Members : 2
         Slots : [UU]
   Failed disk : none
     This Slot : 1
   Sector Size : 512
    Array Size : 1875396608 (894.26 GiB 960.20 GB)
  Per Dev Size : 937698568 (447.13 GiB 480.10 GB)
 Sector Offset : 0
   Num Stripes : 3662884
    Chunk Size : 128 KiB
      Reserved : 0
 Migrate State : idle
     Map State : normal
   Dirty State : clean
    RWH Policy : off
     Volume ID : 1

 Disk00 Serial : YG952300KC480BGN
         State : active
            Id : 00000001
   Usable Size : 937698304 (447.13 GiB 480.10 GB)

Any info on what happened with IMSM driver in 6.x.x?

I guess CONFIG_MD_AUTODETECT is responsible for that, which is Y in
both kernels (as well as CONFIG_BLOCK_LEGACY_AUTOLOAD).
--
@midenok