[4149] in linux-scsi channel archive
Re: Timeout errors with ncr53c895
daemon@ATHENA.MIT.EDU (Gerard Roudier)
Wed Jun 17 20:59:07 1998
Date: Wed, 17 Jun 1998 20:57:50 +0200 (MET DST)
From: Gerard Roudier <groudier@club-internet.fr>
To: Oscar Fernandez Cantero <ofcantero@ceife.es>
cc: linux-scsi@vger.rutgers.edu
In-Reply-To: <3587AA9C.C72CD573@ceife.es>
On Wed, 17 Jun 1998, Oscar Fernandez Cantero wrote:
> Hello SCSIers of the world,
>
> I have recently got a Symbios SYM8951U Ultra2 card with NCR53C895 SCSI
> chip.
> I use it with 3 Cheetah Ultra2 drives in a raid0 configuration.
> I use kernel 2.0.34 patched with driver NCR53C8XX version 3.0 (the last
> I think).
>
> When I use them in 20MHz mode (40Mb/s selectable in the setup utility of
> the card)
> all works fine. But when I try changing to 40MHz mode (Ultra2 mode) the
> configuration
> continues to be usable, but at arbitrary times an error arises that
> suspends
> the SCSI bus for a moment.
Terminations is not the problem if you've attached a device at
each end of the the SCSI BUS (the adapter is a device) and
have enabled terminations on these devices only (The SYMBIOS
Board uses auto-termination, but I donnot know about the Cheatah).
BTW, a termination problem probably will break FAST-20 transfers too.
Cabling is probably another story. There are some requirements for
differential characteristic impedance and minimum spacing between
stub connections that may break FAST-40 but not FAST-20 LVD.
> The error says:
>
>
> scsi : aborting command due to timeout : pid 186838, scsi2, channel 0,
> id 2, lun 0 Read (6) 00 a5 48 30 00
> ncr53c8xx_abort: pid=186838 serial_number=186870
> serial_number_at_timeout=186870ncr53c895-0: abort ccb=013dd020 (cancel)
> scsi : aborting command due to timeout : pid 186837, scsi2, channel 0,
> id 1, lun 0 Read (6) 00 a5 48 36 00
> ncr53c8xx_abort: pid=186837 serial_number=186869
> serial_number_at_timeout=186869ncr53c895-0: abort ccb=06488820 (cancel)
[ ... ]
> This message sequence use to be repeated indefinitely.
>
> A few of the times it is able to continue, the most I have to kill the
> process
> associated to stop the messages.
>
> If someone could give some useful hints it would be very appreciated.
You should check that the BUS cable is appropriate for LVD and should
use a minimal spacing between devices of at least 0.30 meter.
A device problem or a driver problem is not impossible, but checking
that the BUS is ok is the first thing to do.
Regards,
Gerard.
-
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@vger.rutgers.edu
