From owner-freebsd-bugs  Fri Feb  9 12:58:23 2001
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Date: Fri, 9 Feb 2001 20:57:03 +0100 (CET)
From: =?ISO-8859-1?Q?G=E9rard_Roudier?= <groudier@club-internet.fr>
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To: dwmalone@FreeBSD.ORG
Cc: freebsd-bugs@FreeBSD.ORG
Subject: Re: kern/10641: Default sync rate in ncr SCSI driver is slower than
 Ultra2 allows
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On Fri, 9 Feb 2001 dwmalone@FreeBSD.ORG wrote:

> Synopsis: Default sync rate in ncr SCSI driver is slower than Ultra2 allo=
ws
>=20
> Responsible-Changed-From-To: freebsd-bugs->groudier
> Responsible-Changed-By: dwmalone
> Responsible-Changed-When: Fri Feb 9 05:27:15 PST 2001
> Responsible-Changed-Why:=20
> I know that Gerard looks after the sym driver, not the ncr driver, but
> he is likely to be able to check this simple patch quickly.
>=20
> Gerard - could you cast your eye over the patch (which changed
> SCSI_NCR_DFLT_SYNC from 6 to 12) and one of us can commit it, it if
> looks OK.

You want to use 10 instead as default sync value for ULTRA2 negotiation
to be possible.
- 12 -> 20 Mega-transfers per second
- 11 -> about 33
- 10 -> 40 Mega-blah... -> 80 MB/s in 16 bit Wide mode

Note that SCSI_NCR_DFLT_SYNC was intended to be a default value but not a
minimal value, allowing faster speed to be negotiated after boot through
appropriate user commands. But it seems that the ncr may also checks
against a copy of this value when receiving a SDTR message and thus may
turn this default into min. As a result, using camcontrol after boot=20
may not allow to negotiate Ultra2.

Hmmm... I seem to remember that the ncr behaved correctly regarding this
default sync option before CAM introduction. ??

  G=E9rard.

PS: My recommendation for FreeBSD-3.X (X>=3D3) and later versions would be
sym-2.1.6, currently beta due to the Linux support, but that may well be
very solid under FreeBSD given that it is mostly a repackaging of sym for
portability concern. At user's own risk, obviously, since I didn't try
this latest driver version under FreeBSD-3.X.
          ftp://ftp.tux.org/roudier/drivers/portable/



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