4.8-RELEASE not identifying scsi drives

[Per olof Ljungmark]

A problem with 4.8 reported by myself and Aaron D. Gifford.

Anyone in -stable who knows more?

********

I'm assembling a Compaq 1850R with attached storage system. For the 
built in scsi controller (sym), there are three drives internally on 
channel 1 + 5 drives externally on channel 2.
During boot, I can see all disks being identified first by the machine 
itself and then in the early part of the process (something scrolls by 
talking about BIOS drive numbering).

However, the result is not 8 drives but 5 in total in a mix between the 
channels, see below.

da0 at sym0 bus 0 target 0 lun 0
da0: <COMPAQ AB00931B92 3AS8> Fixed Direct Access SCSI-2 device
da0: 40.000MB/s transfers (20.000MHz, offset 15, 16bit), Tagged Queueing 
Enabled
da0: 8678MB (17773500 512 byte sectors: 255H 63S/T 1106C)
da4 at sym1 bus 0 target 4 lun 0
da4: <COMPAQ MAB3091SC 0814> Fixed Direct Access SCSI-2 device
da4: 40.000MB/s transfers (20.000MHz, offset 16, 16bit), Tagged Queueing 
Enabled
da4: 8678MB (17773500 512 byte sectors: 255H 63S/T 1106C)
da2 at sym0 bus 0 target 2 lun 0
da2: <COMPAQ AB00931B92 3AS8> Fixed Direct Access SCSI-2 device
da2: 40.000MB/s transfers (20.000MHz, offset 15, 16bit), Tagged Queueing 
Enabled
da2: 8678MB (17773500 512 byte sectors: 255H 63S/T 1106C)
da3 at sym1 bus 0 target 3 lun 0
da3: <COMPAQ AB00931B92 3AS8> Fixed Direct Access SCSI-2 device
da3: 40.000MB/s transfers (20.000MHz, offset 15, 16bit), Tagged Queueing 
Enabled
da3: 8678MB (17773500 512 byte sectors: 255H 63S/T 1106C)
da1 at sym0 bus 0 target 1 lun 0
da1: <COMPAQ AB00931B92 3AS8> Fixed Direct Access SCSI-2 device
da1: 40.000MB/s transfers (20.000MHz, offset 15, 16bit), Tagged Queueing 
Enabled
da1: 8678MB (17773500 512 byte sectors: 255H 63S/T 1106C)


Aaron D. Gifford wrote:

We ran into a perhaps similar problem with 4.8-RELEASE and 4.8-STABLE 
when we attempted to upgrade an old Compaq Proliant machine on Friday. 
Under 4.7, the sym driver would see all 5 SCSI drives.  But after a 
CVSupdate and build/install of world and reboot, the machine failed to 
boot because the first drive, the root drive, was no longer visible to 
the kernel.  The FreeBSD boot loader could still see the drive, but the 
kernel would never detect it.

At first we couldn't figure out what was going wrong.  After some hours 
including an attempt to install 4.8-RELEASE on another drive that also 
failed because of the disappearing drive problem, we reinstalled 
4.7-RELEASE and have been running RELENG_4_7 since.  I think our old 
system uses the NCR 875 chipset.

Anyone know what changes between 4.7 and 4.8 to sym might be responsible 
for the disappearing drive trick?