Nakamichi MBR-7 / SCSI hangs system

Nakamichi MBR-7 / SCSI hangs system

Post by Leonard N. Zubkof » Fri, 23 Aug 1996 04:00:00



   System: 486DX2/66
           20 mb
           Slackware LINUX 2.0 (Slackware 96)
           Buslogic Kt-545c SCSI interface
                   1 1.08 Gb hard disk scsi #1
                   1 cdrom Nakamichi MBR-7 (7 disks) scsi #3
                   1 iomega Zip drive scsi #5
           Vibra16 sound card & 6x Mitsumi CdRom Drive

  Problem:

  When "Probe all LUNs on each SCSI device" kernel configuration
  option is enabled, about every 30 seconds the system hangs for a
  few seconds (which is going to drive me nuts), I hear the mbr-7
  reset and every thing operates normally again.

  The syslog reports:

  scsi : aborting command due to timeout
  : pid 3146, scsi0, channel 0, id 3, lun 0 Read (6) 16 20 10 02 00
  pau kernel: scsi0: Unable to Abort CCB #3151 to Target 3 - Abort
   Tag Not Supported
  Aug 18 12:39:59 pau kernel:
  SCSI host 0 abort (pid 3146) timed out - resetting
  Aug 18 12:39:59 pau kernel:
  SCSI bus is being reset for host 0 channel 0.
  Aug 18 12:39:59 pau kernel:
  scsi0: Tagged Queuing now disabled for Target 3
  Aug 18 12:39:59 pau kernel:
  scsi0: Sending Bus Device Reset CCB #3153 to Target 3

I'm rather surprised that the MBR-7 supports tagged queuing.  I'll have to
check into this.  In any event, the above messages are quite consistent
with commands timing out and the system resetting the device or bus to
recover.

  Question:

  The CDRom howto in section 6.13 mentions the MBR-7 and the
  probe all lun kernel config switch but also mentions:
  "At least one user also had to increase a SCSI timeout
  value in the kernel driver. " but does not provide any
  detail on what scsi timeout value.  

It would be the value in linux/drivers/scsi/sr.c, I expect.

  Does anyone know what SCSI timeout value is referenced and
  is this timeout value pertinent to this problem ?

Yes, it is definitely pertinent.  Try increasing SR_TIMEOUT from (30 * HZ)
to  (60 * HZ) and see if that helps.

By the way, you shouldn't need to set the "Probe all LUNs on each SCSI
device" option any more.  This should be done automatically for the MBR-7.

                Leonard

 
 
 

Nakamichi MBR-7 / SCSI hangs system

Post by Jack Margeris » Sat, 24 Aug 1996 04:00:00


 System: 486DX2/66
         20 mb
         Slackware LINUX 2.0 (Slackware 96)
         Buslogic Kt-545c SCSI interface
                 1 1.08 Gb hard disk scsi #1
                 1 cdrom Nakamichi MBR-7 (7 disks) scsi #3
                 1 iomega Zip drive scsi #5
         Vibra16 sound card & 6x Mitsumi CdRom Drive

Problem:

When "Probe all LUNs on each SCSI device" kernel configuration
option is enabled, about every 30 seconds the system hangs for a
few seconds (which is going to drive me nuts), I hear the mbr-7
reset and every thing operates normally again.

The syslog reports:

scsi : aborting command due to timeout
: pid 3146, scsi0, channel 0, id 3, lun 0 Read (6) 16 20 10 02 00
pau kernel: scsi0: Unable to Abort CCB #3151 to Target 3 - Abort
 Tag Not Supported
Aug 18 12:39:59 pau kernel:
SCSI host 0 abort (pid 3146) timed out - resetting
Aug 18 12:39:59 pau kernel:
SCSI bus is being reset for host 0 channel 0.
Aug 18 12:39:59 pau kernel:
scsi0: Tagged Queuing now disabled for Target 3
Aug 18 12:39:59 pau kernel:
scsi0: Sending Bus Device Reset CCB #3153 to Target 3

Question:

The CDRom howto in section 6.13 mentions the MBR-7 and the
probe all lun kernel config switch but also mentions:
"At least one user also had to increase a SCSI timeout
value in the kernel driver. " but does not provide any
detail on what scsi timeout value.  

Does anyone know what SCSI timeout value is referenced and
is this timeout value pertinent to this problem ?

                                        Thanks !
                                          jack