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Date:      Mon, 9 Jun 1997 13:04:30 +0200
From:      Stefan Esser <se@FreeBSD.ORG>
To:        Bob Willcox <bob@luke.pmr.com>
Cc:        Matt Thomas <matt@3am-software.com>, hackers@FreeBSD.ORG
Subject:   Re: Does SMC9332BDT work in 2.2.2R??
Message-ID:  <19970609130430.15404@mi.uni-koeln.de>
In-Reply-To: <19970607153951.39100@luke.pmr.com>; from Bob Willcox on Sat, Jun 07, 1997 at 03:39:51PM -0500
References:  <19970607104634.19370@luke.pmr.com> <3.0.1.32.19970607123815.006bc784@ranier.altavista-software.com> <19970607153951.39100@luke.pmr.com>

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On Jun 7, Bob Willcox <bob@luke.pmr.com> wrote:
> On Sat, Jun 07, 1997 at 12:38:15PM -0400, Matt Thomas wrote:
> > At 10:46 AM 6/7/97 -0500, Bob Willcox wrote:
> > >I am trying to install some SMC9332BDT ethernet cards in some of
> > >my systems here with no success. 
> > 
> > grab http://www.3am-software.com/de-970603.tar.gz
> 
> Hmm, my previous response indicating success may have been a bit
> premature.  The above referenced driver works ok on one of my 166MHz
> Pentium systems but fails on my 233MHz PentiumPro system.  Looks
> like there might be a timing or compatibility problem there.  The
> mother board is an ASUS P/I-XP6NP5 with 128MB of memory and all 5
> PCI slots populated (3 SCSI adapters [NCR/SYMBIOS] and a #9 GXE64Pro
> graphics card are in the other 4).
> 
> The system gets through probing and boot ok, but as it starts to
> bring up network daemons they either hang or get RPC timeouts.
> BTW, this behavior is the same with either my new SMC9332DBT or my
> old 21040 based card (its DEC adapter, but I don't know model number
> off hand)

Not sure whether this is actually what hit you,
but there is one feature of PCI motherboards 
with more than 4 PCI slots, that is worth 
mentioning:

If you got 5 PCI slots, then you may still only
have 4 PCI bus-master devices, since that is the 
maximum supported by current Intel PCI chip sets 
(don't have too much information about other 
vendor's chip sets, but guess they have the same
limitation).

Now, you may hit this limit with 3 SCSI cards,
already, since the PCI to ISA bridge may count 
as an additional bus-master (in order to support
ISA DMA). [I don't remember off-hand, whether the 
Triton, Triton 2 and Natoma support 4 masters 
besides the ISA bridge, but you will find that 
information in the publicly available data sheets. 
I'll have a look, when I find the time ...]

There are no slots that don't support bus-master
cards in current PCI motherboards (there used to
be both slot types in some cheap 486MBs). The PCI
BIOS is responsible for the assignment of arbiter
control lines to PCI slots, instead.

You will normally not hit the PCI bus-master limit 
with 4 PCI slot motherboards, since one slot is
expected to hold a graphics card, which is a pure
slave device ...

The solution to your problem seems to be the use
of multi-channel adapter boards (i.e. Adaptec 3940),
since the PCI bridge contains an arbiter of its 
own for the secondary PCI bus, and is seen as just
a single bus-master from the primary PCI bus.
(You could also choose to install your existing 
2940 cards in a PCI extender box, which uses PCI
to PCI bridges to connect one or more PCI buses 
to your motherboard.)

Regards, STefan



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