Re: [PATCH] pci: Omit error message for benign allocation failure

Gary Hade
2007-12-04T21:49:31Z

On Tue, Dec 04, 2007 at 02:35:48PM -0500, Jun'ichi Nomura wrote:
> Hi,
>
> On a system with PCI-to-PCI bridges, following errors are observed:
>
> PCI: Failed to allocate mem resource #8:100000@d8200000 for 0000:02:00.0
> PCI: Failed to allocate mem resource #6:10000@0 for 0000:03:01.0
>
> '#6' is for expansion ROM and '#8' for the bridge where the device
> with the expansion ROM is connected.

I believe there is a good chance that may be another instance
of the regression caused by my "Avoid creating P2P prefetch
window for expansion ROMs" patch that was recently reported by
Jan Beulich.
http://marc.info/?l=linux-kernel&m=119555581103023&w=2

You might want to try reverting my changes to see if the
problem disappears.

I am working on a better fix for the problem that the patch
was attempting to address but this is turning out to be much
more difficult than I expected. If I don't have a solution
very soon I plan to publish a revert patch.

> But I think the failure is benign because the allocation is
> not necessary for these resources.

This is an interesting idea. Could you elaborate? As far
as I can tell, the kernel always tries to allocate memory
for expansion ROMs which it also exports to user level.
I have assumed that some drivers or user level apps may
need to access this space. Is this not true?

If this is due to my change, sorry for the trouble.