From: Benjamin Herrenschmidt <benh@kernel•crashing.org>
To: Shawn Jin <shawnxjin@gmail•com>
Cc: ppcdev <linuxppc-dev@ozlabs•org>
Subject: Re: MSI support on Linux PCI implementation for Ocotea
Date: Sat, 17 Jun 2006 08:13:17 +1000 [thread overview]
Message-ID: <1150495997.23600.52.camel@localhost.localdomain> (raw)
In-Reply-To: <c3d0340b0606161445w5acb4da8j26870f56a4bf4d9@mail.gmail.com>
On Fri, 2006-06-16 at 14:45 -0700, Shawn Jin wrote:
> Hi Ben,
>
> > Now, regarding MSI, as you have noticed, the situation isn't great. I'm
> > currently in the middle of reworking our interrupt management (and
> > interrupt numbers allocation layer) and Michael Ellermann is looking at
> > the MSI issue in parallel.
>
> Just one point about MSI(-X) message address and data format. I think
> it should be the platform that defines the content.
That's an obvious requirement :)
> Current
> implementation doesn't have this flexibility. We have a design where
> MSI mode uses message data to carry vector number info while MSI-X
> mode uses message address to carry this info. Although it seems
> strange, but I think it's allowed by the spec.
The current implementation is bad :) There are some patches for altix
that are in -mm that add some platform hooks that make the situation a
little bit better, but it's still far from perfect.
Ben.
prev parent reply other threads:[~2006-06-16 22:13 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-06-15 21:14 MSI support on Linux PCI implementation for Ocotea Shawn Jin
2006-06-15 23:22 ` Benjamin Herrenschmidt
2006-06-15 23:31 ` Roland Dreier
2006-06-16 0:45 ` Shawn Jin
2006-06-16 21:45 ` Shawn Jin
2006-06-16 22:13 ` Benjamin Herrenschmidt [this message]
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