Subject: Re: Revised BCM selection process

From: Peter Johansson <[email-masked]>
Date: Wed, 5 May 1999 15:01:47 EDT

In a message dated 99-05-04 17:08:30 EDT, [email-masked] writes:

<<Then, why the BCM shall allocate #31 in step g)? If #31 is allocated by
some other applications or by some other nodes, what the BCM should do? Note
that current typical BCM is implemented by the software, it is NOT guaranteed
that the BCM process is fastest.>>

It is theoretically impossible for some other node to allocate channel 31,
since the BCM owns the CHANNELS_AVAILABLE register. But I take your point
about software implementations of the BCM.

I think what is happening here is that the BCM is being transformed into a
FUNDAMENTAL building block for Serial Bus, consequently one that shall be
implemented somewhere other than a driver whose very loading may be deferred.

BCM CAPABILITY NEEDS TO BE IN THE SAME COMPONENT THAT IMPLEMENTS THE IRM,
WHETHER THAT IS HARDWARE OR SOFTWARE.

If this poses problems of migration from the current practives, let's see
what we can do to solve the problem.

<<For others' information, 'bcm_ID' field in the BROADCAST_CHANNEL register
is removed by this revision. Are there any other big changes?>>

To the best of my understanding, Kenji, no. The selection algorithm is
modified and the bcm_ID field is removed.

Regards,

Peter Johansson

Congruent Software, Inc.
98 Colorado Avenue
Berkeley, CA  94707

(510) 527-3926
(510) 527-3856 FAX

[email-masked]

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From: Kenji Fujisawa <[email-masked]>
Date: Fri, 7 May 1999 10:57:50 +0900

I could not find how to disable the Physical Request function for
the Bus Management CSR registers (such as CHANNELS_AVAILABLE reg)
in the OHCI spec 1.0.  Would you teach me if it exists?

If it can't be disabled, it means we can not achieve following
restriction by the OHCI 1.0.

>>WHETHER THAT IS HARDWARE OR SOFTWARE.

I think it can not be accepted in the real world.

I prefer following approach.

:Also, I think dynamic allocation increases the probability of proper
:operation in implementations where the BCM and IRM are implemented within
:different modules.

Kenji Fujisawa