Subject: Signature/Asynch write vs. Asynch stream

From: "Michael D. Johas Teener" <[email-masked]>
Date: Tue, 19 Jan 1999 10:36:06 -0800

I disagree, although you can talk me out of it:

One major reason to use asynch writes (vs. asynch streams) is to take
advantage of the direct memory mapped addressing ... in an OpenHCI
environment, the writes would go directly to some direct mapped
section of system memory (i.e., some portion of the buffer control is
in the source node). In this case, *ALL* of the 1394 packet header is
lost after the packet is written to memory (just like all the PCI
control info is lost after a PCI memory write completes).

I think this means you have to count on the GASP header *all* the time.

At 12:00 AM -0800 1/14/99, Automatic digest processor wrote:
> Date:    Wed, 13 Jan 1999 08:54:20 -0800
> From:    "Hattig, Myron" <[email-masked]>
> Subject: Re: ARP, MCAP, signature
>
> It sounds like we have consensus; the signature should be removed from
> the link fragment header. In the case of async stream, we will use the
> source id in the GASP header. In the case of async writes, we will use
> the source id from the 1394 packet header.
>
> Anyone disagree?
>
> -myron

========================================================================
Michael D. Johas Teener, Chief Technical Officer, Zayante, Inc.
269 Mt. Hermon Rd. #201, Scotts Valley, CA 95066-4000, USA
voice: +1-831-461-4901  fax: +1-831-461-1394  page: [email-masked]
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======================== http://www.zayante.com ========================

---

From: "Wooten, David" <[email-masked]>
Date: Tue, 19 Jan 1999 13:15:16 -0600

OK, let me talk you out of this.  In OHCI, there are portions of space that
are above physical memory.  Writes to those spaces go to the GRU where all
of the packet header information is retained.  It is expected that any time
datagram services are needed, an address in memory that goes to the GRU will
be given as the address to be used so that the header information will be
retained.

I think that it would be interesting to look at what should happen for
something like socket services.  I believe that packets sent would be able
to be sent to either physical memory or to GRU 'memory'.  Is that right?

David Wooten

> -----Original Message-----
> From: Michael D. Johas Teener [mailto:[email-masked]]
> Sent: Tuesday, January 19, 1999 12:36 PM
> To: [email-masked]
> Subject: Signature/Asynch write vs. Asynch stream
>
>