Promise ATA RAID broken

[Paul Herman <pherman@xxxxxxxxxxxxxxx>]

Hey fellas,

I updated a machine to 1.0-RELEASE (was running a March 12th 
system) and the ATA RAID array is no longer readable.

It seems that while probing, the kernel ATA driver inadvertently 
resets the RAID configuration.  Because the array is also my '/' 
file system, I'm dropped into the mountprompt> and the only thing 
to do is to reboot.  After reboot you need to enter the Promise 
BIOS and reconfigure the damaged arrays.

When it works, the dmesg looks like:

  atapci0: <Promise TX2 ATA133 controller> port 0xcc00-0xcc0f,0xc800-0xc803,0xc400-0xc407,0xc000-0xc003,0xbc00-0xbc07 mem 0xe2040000-0xe2043fff irq 11 at device 10.0 on pci2
  [...]
  ar0: 1907348MB <ATA RAID1 array> [46544/255/63] status: READY subdisks:
    0 READY ad4: 239372MB <Maxtor 6Y250P0> [486344/16/63] at ata2-master UDMA133
          1 READY ad6: 239372MB <Maxtor 4A250J0> [486344/16/63] at ata3-master UDMA133

I couldn't save the broken dmesg, but I'm pretty sure it says the 
same thing as above, but then afterward it says:
  ar0: ERROR - array broken

My guess is that somehow the configuration gets changed and then 
the change gets picked up by ata-raid.c:ar_config_changed() which 
reports it broken.  Some sort of bad reset?  Anyone out there with 
any ATA foo?

A kernel from March 12th (the only other one I have available) 
works fine.  I'm unfortunately not in a position to do a binary 
date search on the offending change.

-Paul.