Re: Fw: why Master/Target cannot change its mind

[Wen-King Su <wen-king@myri.com>]

>From: =?ISO-8859-1?Q?G=E9rard_Roudier?= <groudier@club-internet.fr>
>
>Weng,
>
>In my initial response to your proposal, I described a situation that
>harms when the master changes its mind after having asserted IRDY#.
>
>The situation corresponds to a master reading to non-prefetchable.

Prefetchability and side-effect are two different things.  A read to a
temperature sensor is non-prefetchable, but it does not have to have
any side effects.  What you are referring to here is read with side
effects.

I think what weng described is a bit incomplete.  In particular, I
would like to know what happens to FRAME# when IRDY# changes.  While
not endorsing weng's proposal, I would say with the right FRAME#
behavior, I see no more problems regarding read side-effects as
compared to regular PCI.  Remember, target cannot wait for IRDY#
to be asserted as a pre-condition to its asserting TRDY#.