Michael Smith wrote:
> > Yeah, you do.  I fully understood _that_ context; I think Mike
> > was talking about other context.  It's pretty clear to me that
> > ranges ought to be per bridge chipset, rather than global... I
> > thought that that was what the option was working around: that
> > they were not.
> I can't imagine how you came to this conclusion.  You won't get it from
> reading the code, or from understanding how PCI works.  Maybe you need
> sleep too.

I got it from assuming that reading the code didn't tell me how
the code was supposed to work, because if it had, then this would
never had been a discussion, because the code would always do the
right thing.  8-).  My 1.0 copy of the PCI-PCI bridge documentation
doesn't say that what Alfred's system is doing is bad; maybe it's
just outdated.

> The problem is twofold:
>  - The code is broken, it fails to take into account both prefetched and
>    non-prefetched bridge mappings.  It also appears to miscompute the
>    start of one of the attempted range accesses.

Cool... this is the bug description I was fishing for here.

>  - There is anecdotal evidence that some bridges pass ranges other than
>    those advertised in their mappings, so even if the first problem is
>    resolved, enforcing correctness may result in occasional lossage.

This sounds like a job for a "panic: anecdotal is real!" that Alfred
could jam into the code, since he has the magic hardware.

> And, since you ask, the whole reason behind having this code in the
> first place is that we need to be able to correctly assign resources for
> devices behind bridges.

Yeah; it was the "it not doing it for Alfred's weird hardware" thing
that threw me off.  8-) 8-).

> I got run over by a car last time I worked on this code.  Time for
> someone else to pick it up.

Oh yeah, we're *all* going to jump on hacking that code, now
that you told us it's cursed!  }B^D.

Alfred, since you have the hardware that can (maybe) prove the
anedote real, and can demonstrably show that Mike's problem
#1 is fixed, once it's fixed...  care to brave the curse?

-- Terry

To Unsubscribe: send mail to [EMAIL PROTECTED]
with "unsubscribe freebsd-current" in the body of the message

Reply via email to