odd dmesg scsi error with aic7902 controller

Have just moved to supermicro 1U boxes using 80-pin SCA drives (Seagate
ST336607LC) and U320 adaptec on-board controllers (aic7902) and the 
error shown in the dmesg below crops up during bootup.

The odd thing is that it only occurs if 2 or more drives are connected;
if only 1 drive is physically attached, the boot up sequence is smooth.
These boxes are not yet in production and I hesitate to do so if the
error message is an indication of future problems. This same message
does occur in FreeBSD 4.9-Release also. The following dmesg snippet
comes from a 5.2.1-Release system:

FreeBSD 5.2.1-RELEASE #0: Mon Feb 23 20:45:55 GMT 2004
    root_at_wv1u.btc.adaptec.com:/usr/obj/usr/src/sys/GENERIC
Preloaded elf kernel "/boot/kernel/kernel" at 0xc0a35000.
Preloaded elf module "/boot/kernel/acpi.ko" at 0xc0a352e4.
ACPI APIC Table: <PTLTD          APIC  >
Timecounter "i8254" frequency 1193182 Hz quality 0
CPU: Intel(R) Xeon(TM) CPU 2.40GHz (2399.33-MHz 686-class CPU)
  Origin = "GenuineIntel"  Id = 0xf29  Stepping = 9
 
Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE>
  Hyperthreading: 2 logical CPUs
real memory  = 2146959360 (2047 MB)
avail memory = 2080153600 (1983 MB)
FreeBSD/SMP: Multiprocessor System Detected: 4 CPUs
.
.
.
ahd0: <Adaptec AIC7902 Ultra320 SCSI adapter> port
0x4000-0x40ff,0x4400-0x44ff mem 0xfc300000-0xfc301fff irq 28 at device
2.0 on pci3
aic7902: Ultra320 Wide Channel A, SCSI Id=7, PCI-X 101-133Mhz, 512 SCBs
ahd1: <Adaptec AIC7902 Ultra320 SCSI adapter> port
0x4800-0x48ff,0x4c00-0x4cff mem 0xfc302000-0xfc303fff irq 29 at device
2.1 on pci3
aic7902: Ultra320 Wide Channel B, SCSI Id=7, PCI-X 101-133Mhz, 512 SCBs
.
.
.
Waiting 15 seconds for SCSI devices to settle
ahd0: Invalid Sequencer interrupt occurred.
>>>>>>>>>>>>>>>>>> Dump Card State Begins <<<<<<<<<<<<<<<<<
ahd0: Dumping Card State at program address 0x216 Mode 0x0
Card was paused
HS_MAILBOX[0x0] INTCTL[0x80]:(SWTMINTMASK) SEQINTSTAT[0x0]
SAVED_MODE[0x11] DFFSTAT[0x33]:(CURRFIFO_NONE|FIFO0FREE|FIFO1FREE)
SCSISIGI[0x0]:(P_DATAOUT) SCSIPHASE[0x0] SCSIBUS[0x0]
LASTPHASE[0x1]:(P_DATAOUT|P_BUSFREE) SCSISEQ0[0x0]
SCSISEQ1[0x12]:(ENAUTOATNP|ENRSELI) SEQCTL0[0x0]
SEQINTCTL[0x6]:(INTMASK1|INTMASK2)
SEQ_FLAGS[0x0] SEQ_FLAGS2[0x0] SSTAT0[0x0] SSTAT1[0x0]
SSTAT2[0x0] SSTAT3[0x0] PERRDIAG[0x0]
SIMODE1[0xa4]:(ENSCSIPERR|ENSCSIRST|ENSELTIMO)
LQISTAT0[0x0] LQISTAT1[0x0] LQISTAT2[0x0] LQOSTAT0[0x0]
LQOSTAT1[0x0] LQOSTAT2[0x0]

SCB Count = 16 CMDS_PENDING = 0 LASTSCB 0xffff CURRSCB 0x9 NEXTSCB
0xff80
qinstart = 38 qinfifonext = 41
QINFIFO: 0xe 0x9 0xf
WAITING_TID_QUEUES:
Pending list:
 15 FIFO_USE[0x0] SCB_CONTROL[0x40]:(DISCENB) SCB_SCSIID[0x17]
  9 FIFO_USE[0x0] SCB_CONTROL[0x40]:(DISCENB) SCB_SCSIID[0x7]
 14 FIFO_USE[0x0] SCB_CONTROL[0x48]:(STATUS_RCVD|DISCENB)
SCB_SCSIID[0x7]
Total 3
Kernel Free SCB list: 1 2 3 4 5 6 7 8 10 11 12 13 0
Sequencer Complete DMA-inprog list:
Sequencer Complete list:
Sequencer DMA-Up and Complete list:

ahd0: FIFO0 Free, LONGJMP == 0x8000, SCB 0xf
SEQIMODE[0x3f]:(ENCFG4TCMD|ENCFG4ICMD|ENCFG4TSTAT|ENCFG4ISTAT|ENCFG4DATA|ENSAVEPTRS)
SEQINTSRC[0x0] DFCNTRL[0x0] DFSTATUS[0x89]:(FIFOEMP|HDONE|PRELOAD_AVAIL)
SG_CACHE_SHADOW[0x2]:(LAST_SEG) SG_STATE[0x0] DFFSXFRCTL[0x0]
SOFFCNT[0x0] MDFFSTAT[0x5]:(FIFOFREE|DLZERO) SHADDR = 0x00, SHCNT = 0x0
HADDR = 0x00, HCNT = 0x0 CCSGCTL[0x10]:(SG_CACHE_AVAIL)
ahd0: FIFO1 Free, LONGJMP == 0x8063, SCB 0x9
SEQIMODE[0x3f]:(ENCFG4TCMD|ENCFG4ICMD|ENCFG4TSTAT|ENCFG4ISTAT|ENCFG4DATA|ENSAVEPTRS)
SEQINTSRC[0x0] DFCNTRL[0x0] DFSTATUS[0x89]:(FIFOEMP|HDONE|PRELOAD_AVAIL)
SG_CACHE_SHADOW[0x2]:(LAST_SEG) SG_STATE[0x0] DFFSXFRCTL[0x0]
SOFFCNT[0x0] MDFFSTAT[0x5]:(FIFOFREE|DLZERO) SHADDR = 0x00, SHCNT = 0x0
HADDR = 0x00, HCNT = 0x0 CCSGCTL[0x10]:(SG_CACHE_AVAIL)
LQIN: 0x8 0x0 0x0 0xf 0x0 0x1 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0
0x0 0x0 0x0 0x0
ahd0: LQISTATE = 0x0, LQOSTATE = 0x0, OPTIONMODE = 0x52
ahd0: OS_SPACE_CNT = 0x20 MAXCMDCNT = 0x1

SIMODE0[0xc]:(ENOVERRUN|ENIOERR)
CCSCBCTL[0x4]:(CCSCBDIR)
ahd0: REG0 == 0xb660, SINDEX = 0x10e, DINDEX = 0x104
ahd0: SCBPTR == 0xf, SCB_NEXT == 0xff80, SCB_NEXT2 == 0xffc8
CDB 12 20 0 80 88 a6
STACK: 0x211 0x2 0x0 0x0 0x0 0x0 0x0 0x0
>>>>>>>>>>>>>>>>>
ses0 at ahd0 bus 0 target 6 lun 0
ses0: <SUPER GEM318 0> Fixed Processor SCSI-2 device
ses0: 3.300MB/s transfers
ses0: SAF-TE Compliant Device
GEOM: create disk da0 dp=0xc86c8850
GEOM: create disk da1 dp=0xc86cd050
Copied 18 bytes of sense data offset 12: 0x70 0x0 0x6 0x0 0x0 0x0 0x0
0xa 0x0 0x0 0x0 0x0 0x29 0x2 0x2 0x0 0x0 0x0
SMP: AP CPU #2 Launched!
SMP: AP CPU #1 Launched!
SMP: AP CPU #3 Launched!
Copied 18 bytes of sense data offset 12: 0x70 0x0 0x6 0x0 0x0 0x0 0x0
0xa 0x0 0x0 0x0 0x0 0x29 0x2 0x2 0x0 0x0 0x0
da0 at ahd0 bus 0 target 0 lun 0
da0: <SEAGATE ST336607LC 0007> Fixed Direct Access SCSI-3 device
da0: 320.000MB/s transfers (160.000MHz, offset 63, 16bit), Tagged
Queueing Enabled
da0: 35003MB (71687372 512 byte sectors: 255H 63S/T 4462C)
da1 at ahd0 bus 0 target 1 lun 0
da1: <SEAGATE ST336607LC 0007> Fixed Direct Access SCSI-3 device
da1: 320.000MB/s transfers (160.000MHz, offset 63, 16bit), Tagged
Queueing Enabled
da1: 35003MB (71687372 512 byte sectors: 255H 63S/T 4462C)

Has anyone seen anything similar or have any ideas? these drives are
running the latest Seagate firmware and the system bios is the latest
available. Would this question be more suited for the scsi mailing list?

The message on the 4.9-Release is pretty much identical except using
pass3 in place of ses0/GEOM

Sven