Adaptec AHD U320 operating as only U160

Niki Denev nike_d at
Sat Feb 16 23:06:03 UTC 2008

On Feb 12, 2008 3:08 AM, David O'Brien <obrien at> wrote:
> On Mon, Feb 11, 2008 at 02:51:10PM -0700, Scott Long wrote:
> > I hate to say it, but SCSI speed negotiation broke with 7.0.
> ...
> > I'm working on fixing the problem, but it won't be fixed in time for
> > the final 7.0 release.
> I know.
> I hope I've added to the body of knowledge of where the problem started.
> You told me previously it could have been the addition of the Domain
> Validation code.  Unfortuantely it isn't - it goes all teh way back to
> the cut over to the "NEW TRANS" code.
> > and I don't know of a workaround other than to tell you to read the
> > camcontrol manpage section on the 'negotiate' command and play with
> > that.
> Using that I am not able to get U320  negotiatation.
> --
> -- David  (obrien at

I was playing around with DTrace, tracing cam/xpt and the ahd driver and
found out that if i comment the following code :

        if ((spi3caps & SID_SPI_IUS) == 0)
                spi->ppr_options &= ~MSG_EXT_PPR_IU_REQ;

at line 6655 in sys/cam/cam_xpt.c my disks again negotiate as U320 :

  da0 at ahd0 bus 0 target 0 lun 0
  da0: <SEAGATE ST336807LW 0C01> Fixed Direct Access SCSI-3 device
  da0: 320.000MB/s transfers (160.000MHz DT, offset 63, 16bit)
  da0: Command Queueing Enabled
  da0: 35003MB (71687372 512 byte sectors: 255H 63S/T 4462C)

Unfortunately I began seeing again the "Invalid sequencer interrupt"
messages that i was
seeing before(with fbsd 6.2) with Seagate drives on Adaptec at U320 speeds,
and I prey that they are harmless (as they used to be?)

Of course this might be (and possibly is :) ) completely wrong,
but i hope it can serve as a pointer to the problem with the negotiation.


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