From: Matthew Wilcox <willy@debian.org>
To: Jeff Garzik <jgarzik@pobox.com>
Cc: linux-kernel@vger.kernel.org,
Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
willy@debian.org, davem@redhat.com
Subject: Re: Message Signalled Interrupt support?
Date: Mon, 12 May 2003 17:53:31 +0100 [thread overview]
Message-ID: <20030512165331.GZ29534@parcelfarce.linux.theplanet.co.uk> (raw)
In-Reply-To: <20030512163249.GF27111@gtf.org>
On Mon, May 12, 2003 at 12:32:49PM -0400, Jeff Garzik wrote:
> Has anybody done any work, or put any thought, into MSI support?
Work -- no. Thought? A little. Seems to me that MSIs need to be treated
as a third form of interrupts (level/edge/message). The address that
the MSI will write to is clearly architecture dependent (may even be
irq-controller-dependent, depending on your architecture). request_irq()
is an insufficient function to deal with this -- request_msi() may be
needed instead. It'll need to return an address to pass to the card.
(We need a mechanism to decide whether it's a 32-bit or 64-bit address).
Oh, and don't make this too PCI-specific -- native PARISC interrupts
are MSI and you can see how handled it in arch/parisc/kernel/irq.c.
> Would things massively break if I set up MSI manually in the driver?
Might do, might not.
--
"It's not Hollywood. War is real, war is primarily not about defeat or
victory, it is about death. I've seen thousands and thousands of dead bodies.
Do you think I want to have an academic debate on this subject?" -- Robert Fisk
next prev parent reply other threads:[~2003-05-12 16:40 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-05-12 16:32 Message Signalled Interrupt support? Jeff Garzik
2003-05-12 16:53 ` Matthew Wilcox [this message]
2003-05-12 17:20 ` David S. Miller
2003-05-12 18:54 ` Mika Penttilä
2003-05-12 17:43 ` Matt Porter
2003-05-12 18:20 ` Matthew Wilcox
2003-05-12 18:48 ` Matt Porter
2003-05-13 11:21 ` Ivan Kokshaysky
2003-05-12 17:26 Chuck Ebbert
2003-05-12 17:53 Nakajima, Jun
2003-05-12 18:26 Nakajima, Jun
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