Bug 186520 - CONFIG_PCI_MSI is not set to y in installed x86_64 2.6.15 kernel for fc5
Summary: CONFIG_PCI_MSI is not set to y in installed x86_64 2.6.15 kernel for fc5
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Fedora
Classification: Fedora
Component: kernel
Version: 5
Hardware: x86_64
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Dave Jones
QA Contact: Brian Brock
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2006-03-24 00:50 UTC by Dave Olson
Modified: 2015-01-04 22:26 UTC (History)
5 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed: 2006-07-16 01:44:34 UTC
Type: ---
Embargoed:


Attachments (Terms of Use)

Description Dave Olson 2006-03-24 00:50:50 UTC
As installed, the .config does not have MSI enabled.   It was
enabled for FC4 and FC3 kernels.  I can't find any reason in
the release notes or lkml for it being disabled.

Our PathScale InfiniPath product requires MSI in order to function,
and I was surprised to find that I had to install the kernel source
rpm and reconfigure in order for MSI to function.

Was this a deliberate change, and if so, what was the reason?

Comment 1 Dave Jones 2006-03-24 22:42:47 UTC
It caused problems booting on some systems.  I don't have the details to hand.


Comment 2 Bryan O'Sullivan 2006-03-27 23:16:15 UTC
This is a big problem for us.

Comment 3 Greg Lindahl 2006-03-31 20:52:23 UTC
1. Our cards are the first of probably many which require MSI. MSI was optional
for PCI-X but is required for PCI Express.

2. Other cards like the Mellanox InfiniBand adaptor run faster with MSI enabled
-- see the OpenIB mailing list for discussion about this a while ago.

I have no doubt that some systems have problems with MSI, but they're broken and
will probably get fixed, for example I spent 2 days arguing with the in-house
BIOS team at a Tier 1 computer vendor (a big Red Hat partner) and they finally
agreed that they needed to fix their BIOS so that MSI worked. It turned out to
be a one-line fix...


Comment 4 Dave Olson 2006-04-03 17:38:43 UTC
It appears that the latest FC 4 2.6.16 kernel now has the same issue, that
is, the default 2.6.16 kernel with FC4 yum update now has CONFIG_PCI_MSI=n

Comment 5 Dave Olson 2006-05-09 05:58:25 UTC
It appears that the latest fc4 update kernels (e.g. 2.6.16-1.2108_FC4smp for
x86_64) now has CONFIG_PSI_MSI=y again, and I'm told FC5 has also reverted
to enabling this.   Should we expect that to remain true for future 
Fedora kernels?

Comment 6 Dave Jones 2006-05-09 23:59:35 UTC
no (it was on as an experiment in fc4, and sneaked into an update
inadvertantly), I'm going to look at enabling it across the board when I rebase
to 2.6.17



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