AIC7902 w/ seagate U320 drive issue on releng-4 (and current)

[Don Bowman]

Well, i've upgraded all my seagate U320 15K RPM drives to rom 005.
This has dramatically improved the reliability. However it is not
perfect. I'm sometimes getting traces as show below. These occur
without particular drive stress (or more frequently with it),
but they seem to track device. E.g. a given PC will either do
this or not do it.

This is not an electrical error (the cable is 1" long).
<SEAGATE ST318453LW 0005>          at scbus0 target 0 lun 0 (pass0,da0)
is the drive in question. I'm running the latest RELENG_4 ahd
driver. This is an SMP system.

I would really appreciate some help on this issue. The message
as below is not typically fatal, things continue on.

(da0:ahd0:0:0:0): SCB 0x16 - timed out
>>>>>>>>>>>>>>>>>> Dump Card State Begins <<<<<<<<<<<<<<<<<
ahd0: Dumping Card State at program address 0x6 Mode 0x33
Card was paused
HS_MAILBOX[0x0] INTCTL[0xc0]:(SWTMINTEN|SWTMINTMASK) 
SEQINTSTAT[0x0] SAVED_MODE[0x11]
DFFSTAT[0x31]:(CURRFIFO_1|FIFO0FREE|FIFO1FREE) 
SCSISIGI[0x0]:(P_DATAOUT) SCSIPHASE[0x0] SCSIBUS[0x0] 
LASTPHASE[0x1]:(P_DATAOUT|P_BUSFREE) SCSISEQ0[0x0] 
SCSISEQ1[0x12]:(ENAUTOATNP|ENRSELI) SEQCTL0[0x10]:(FASTMODE) 
SEQINTCTL[0x0] SEQ_FLAGS[0x0] SEQ_FLAGS2[0x0] SSTAT0[0x0] 
SSTAT1[0x8]:(BUSFREE) SSTAT2[0x0] SSTAT3[0x0] PERRDIAG[0x8]:(AIPERR) 
SIMODE1[0xa4]:(ENSCSIPERR|ENSCSIRST|ENSELTIMO) LQISTAT0[0x0] 
LQISTAT1[0x0] LQISTAT2[0x0] LQOSTAT0[0x0] LQOSTAT1[0x0] 
LQOSTAT2[0x1]:(LQOSTOP0) 

SCB Count = 32 CMDS_PENDING = 4 LASTSCB 0x5 CURRSCB 0x18 NEXTSCB 0xff80
qinstart = 22101 qinfifonext = 22101
QINFIFO:
WAITING_TID_QUEUES:
Pending list:
24 FIFO_USE[0x0] SCB_CONTROL[0x60]:(TAG_ENB|DISCENB) SCB_SCSIID[0x7] 
5 FIFO_USE[0x0] SCB_CONTROL[0x60]:(TAG_ENB|DISCENB) SCB_SCSIID[0x7] 
7 FIFO_USE[0x0] SCB_CONTROL[0x62]:(TAG_ENB|DISCENB) SCB_SCSIID[0x7] 
22 FIFO_USE[0x0] SCB_CONTROL[0x60]:(TAG_ENB|DISCENB) SCB_SCSIID[0x7] 
Total 4
Kernel Free SCB list: 3 15 9 1 8 23 4 21 6 10 11 12 14 25 27 13 29 0 30 28
31 2 26 20 19 18 17 16 
Sequencer Complete DMA-inprog list: 
Sequencer Complete list: 
Sequencer DMA-Up and Complete list: 

ahd0: FIFO0 Free, LONGJMP == 0x80ff, SCB 0x16
SEQIMODE[0x3f]:(ENCFG4TCMD|ENCFG4ICMD|ENCFG4TSTAT|ENCFG4ISTAT|ENCFG4DATA|ENS
AVEPTRS) 
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 == 0x825e, SCB 0x16
SEQIMODE[0x3f]:(ENCFG4TCMD|ENCFG4ICMD|ENCFG4TSTAT|ENCFG4ISTAT|ENCFG4DATA|ENS
AVEPTRS) 
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: 0x55 0x0 0x0 0x16 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0
0x0 0x0 0x0 
ahd0: LQISTATE = 0x0, LQOSTATE = 0x0, OPTIONMODE = 0x42
ahd0: OS_SPACE_CNT = 0x20 MAXCMDCNT = 0x2

SIMODE0[0xc]:(ENOVERRUN|ENIOERR) 
CCSCBCTL[0x4]:(CCSCBDIR) 
ahd0: REG0 == 0x5, SINDEX = 0x133, DINDEX = 0x102
ahd0: SCBPTR == 0x18, SCB_NEXT == 0xff80, SCB_NEXT2 == 0xff34
CDB a 5 b1 9f 20 0
STACK: 0x125 0x0 0x0 0x257 0x240 0x94 0x29 0x1
<<<<<<<<<<<<<<<< Dump Card State Ends >>>>>>>>>>>>>>>>>>
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