From: Roland Dreier <rdreier@cisco.com>
To: "Waskiewicz Jr, Peter P" <peter.p.waskiewicz.jr@intel.com>
Cc: "Nelson, Shannon" <shannon.nelson@intel.com>,
<akpm@linux-foundation.org>, <linux-kernel@vger.kernel.org>,
<davem@davemloft.net>, <jeff@garzik.org>,
"Williams, Dan J" <dan.j.williams@intel.com>,
"Leech, Christopher" <christopher.leech@intel.com>
Subject: Re: [PATCH 5/7] I/OAT: Add support for MSI and MSI-X
Date: Fri, 20 Jul 2007 12:05:24 -0700 [thread overview]
Message-ID: <aday7hac2vf.fsf@cisco.com> (raw)
In-Reply-To: <D5C1322C3E673F459512FB59E0DDC32903445CD4@orsmsx414.amr.corp.intel.com> (Waskiewicz Jr's message of "Fri, 20 Jul 2007 11:09:03 -0700")
> Both igb (recently posted) and ixgbe (also recently posted) support both
> MSI and MSI-X. Right now when we try to request MSI-X vectors, if we
> fail to acquire what we've asked for, we fall back to MSI support. If
> MSI fails to initialize, we fall back to legacy interrupts. So it needs
> to be there in case MSI-X allocation fails for the NIC driver.
Hmm, I see I don't understand what this driver is doing. What is a
"struct ioatdma_device"? Is this driver requesting interrupts that
come from the NIC or the IOAT DMA engine?
Anyway, if the NICs support MSI-X, is there any chance of failing to
get one MSI-X vectors but then succeeding in getting MSI enabled?
How could that happen? I don't see what falling back to MSI buys you
beyond more code.
- R.
next prev parent reply other threads:[~2007-07-20 19:05 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-20 0:44 [PATCH 0/7] I/OAT: Add support for DCA - Direct Cache Access Shannon Nelson
2007-07-20 0:44 ` [PATCH 1/7] I/OAT: New device ids Shannon Nelson
2007-07-20 0:49 ` David Miller
2007-07-20 0:44 ` [PATCH 2/7] I/OAT: Rename the source file Shannon Nelson
2007-07-20 0:49 ` David Miller
2007-07-20 0:45 ` [PATCH 3/7] I/OAT: code cleanup from checkpatch output Shannon Nelson
2007-07-20 0:49 ` David Miller
2007-07-20 0:45 ` [PATCH 4/7] I/OAT: Split PCI startup from DMA handling code Shannon Nelson
2007-07-20 0:50 ` David Miller
2007-07-20 10:53 ` Andrey Panin
2007-07-20 16:33 ` Nelson, Shannon
2007-07-20 0:45 ` [PATCH 5/7] I/OAT: Add support for MSI and MSI-X Shannon Nelson
2007-07-20 0:51 ` David Miller
2007-07-20 17:43 ` Roland Dreier
2007-07-20 18:09 ` Waskiewicz Jr, Peter P
2007-07-20 19:05 ` Roland Dreier [this message]
2007-07-20 19:19 ` Waskiewicz Jr, Peter P
2007-07-20 19:49 ` Roland Dreier
2007-07-20 21:10 ` Leech, Christopher
2007-07-20 21:21 ` Roland Dreier
2007-07-20 21:32 ` Manu Abraham
2007-07-20 21:38 ` Roland Dreier
2007-07-20 21:49 ` Manu Abraham
2007-07-20 21:54 ` Nelson, Shannon
2007-07-20 21:59 ` Manu Abraham
2007-07-20 22:00 ` Nelson, Shannon
2007-07-20 22:07 ` Waskiewicz Jr, Peter P
2007-07-20 21:13 ` Nelson, Shannon
2007-07-20 0:45 ` [PATCH 6/7] DCA: Add Direct Cache Access driver Shannon Nelson
2007-07-20 0:52 ` David Miller
2007-07-20 16:35 ` Nelson, Shannon
2007-07-20 0:45 ` [PATCH 7/7] I/OAT: Add DCA services Shannon Nelson
2007-07-20 0:52 ` David Miller
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