From: "H. Peter Anvin" <hpa@zytor.com>
To: Grant Grundler <grundler@parisc-linux.org>
Cc: Roland Dreier <rdreier@cisco.com>,
David Miller <davem@davemloft.net>,
abraham.manu@gmail.com, greg@kroah.com,
linux-pci@atrey.karlin.mff.cuni.cz, linux-kernel@vger.kernel.org
Subject: Re: PCIE
Date: Sun, 27 May 2007 22:23:14 -0700 [thread overview]
Message-ID: <465A6742.4090903@zytor.com> (raw)
In-Reply-To: <20070528041802.GB711@colo.lackof.org>
Grant Grundler wrote:
> On Sun, May 27, 2007 at 06:03:29PM -0700, Roland Dreier wrote:
> ...
>> > I can imagine many systems where the cpu simply doesn't have enough
>> > interrupt pins to uniquely identify every possible MSI interrupt
>> > source.
>>
>> I have a hard time imagining a PCI host bus controller that converts
>> MSI interrupts back to wire interrupts that go to pins on the CPU.
>> For one thing it would be hard to maintain the guarantee that
>> MSI interrupts can't pass DMAs.
>
> Whatever converts the MSI back to CPU IRQ pins would have to participate
> in the "cache coherency domain". This would avoid issues around DMA ordering.
> It _could_ be on the same silicon as the PCI Host bus controller as long
> as the above is true.
>
Also, don't forget that a lot of platforms provide *no* hardware cache
coherency.
-hpa
next prev parent reply other threads:[~2007-05-28 5:25 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-05-23 12:15 PCIE Manu Abraham
2007-05-23 15:59 ` PCIE Greg KH
2007-05-23 20:59 ` PCIE Manu Abraham
2007-05-23 21:10 ` PCIE Roland Dreier
2007-05-23 22:11 ` PCIE Manu Abraham
2007-05-23 22:23 ` PCIE Roland Dreier
2007-05-23 23:03 ` PCIE Manu Abraham
2007-05-23 23:51 ` PCIE Roland Dreier
2007-05-24 0:07 ` PCIE Manu Abraham
2007-05-24 22:32 ` PCIE Manu Abraham
2007-05-25 3:25 ` PCIE Roland Dreier
2007-05-26 15:03 ` PCIE Manu Abraham
2007-05-26 18:28 ` PCIE Grant Grundler
2007-05-26 19:27 ` PCIE Manu Abraham
2007-05-28 1:15 ` PCIE Roland Dreier
2007-05-28 1:25 ` PCIE Manu Abraham
2007-05-28 2:04 ` PCIE Manu Abraham
2007-05-28 2:24 ` PCIE Roland Dreier
2007-05-28 2:47 ` PCIE Manu Abraham
2007-05-26 22:49 ` PCIE David Miller
2007-05-26 22:57 ` PCIE Manu Abraham
2007-05-26 23:55 ` PCIE Grant Grundler
2007-05-27 0:00 ` PCIE David Miller
2007-05-27 0:16 ` PCIE Grant Grundler
2007-05-27 0:30 ` PCIE David Miller
2007-05-27 1:01 ` PCIE Manu Abraham
2007-05-27 1:49 ` PCIE Grant Grundler
2007-05-27 20:28 ` PCIE Manu Abraham
2007-05-28 1:10 ` PCIE Roland Dreier
2007-05-27 2:34 ` PCIE H. Peter Anvin
2007-05-27 7:40 ` PCIE David Miller
2007-05-27 20:31 ` PCIE Manu Abraham
2007-05-28 1:05 ` PCIE Roland Dreier
2007-05-28 1:03 ` PCIE Roland Dreier
2007-05-28 2:54 ` PCIE David Miller
2007-05-28 4:18 ` PCIE Grant Grundler
2007-05-28 5:23 ` H. Peter Anvin [this message]
2007-05-28 5:22 ` PCIE H. Peter Anvin
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