linux-kernel - Re: pci 0000:01:00.0: BAR 6: no parent found for of device [0xfffe0000-0xffffffff]

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Message-ID: <dd18b0c30906241341r387dcaaaie437df2ff28ae1d8@mail.gmail.com>
Date:	Wed, 24 Jun 2009 13:41:03 -0700
From:	Justin Mattock <justinmattock@...il.com>
To:	Jesse Barnes <jbarnes@...tuousgeek.org>
Cc:	Matthew Wilcox <matthew@....cx>, "Rafael J. Wysocki" <rjw@...k.pl>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Linux PCI <linux-pci@...r.kernel.org>
Subject: Re: pci 0000:01:00.0: BAR 6: no parent found for of device 
	[0xfffe0000-0xffffffff]

On Wed, Jun 24, 2009 at 1:04 PM, Jesse Barnes<jbarnes@...tuousgeek.org> wrote:
> On Wed, 24 Jun 2009 13:50:30 -0600
> Matthew Wilcox <matthew@....cx> wrote:
>
>> On Wed, Jun 24, 2009 at 09:30:07PM +0200, Rafael J. Wysocki wrote:
>> > (Adding CC to linux-pci)
>>
>> Thanks Rafael.
>>
>> > On Wednesday 24 June 2009, Justin Mattock wrote:
>> > > (just pulled the latest git)
>> > > And am seeing this:
>> >
>> > Where pci 0000:01:00.0 and 0000:02:00.0 are what?
>> >
>> > > [    0.696001] pci 0000:01:00.0: BAR 6: no parent found for of
>> > > device [0xfffe0000-0xffffffff]
>>
>> So the message is coming from pci_claim_resource, and
>> if you bother to bisect, you'll track it back to my commit
>> a76117dfd687ec4be0a9a05214f3009cc5f73a42 .  What's going on here,
>> since this is BAR 6, is we have a ROM which has been mapped high, and
>> then not unmapped.  The BAR doesn't fit in the parent's window, so
>> the code is rightly declining to allocate the BAR.
>>
>> Before my patch, we silently didn't allocate the BARs.  Now we print
>> a message.  I wonder what to do ... we could silence this warning in
>> pci_claim_resource (patch below).  Or we could declare this to be a
>> bug, and fix it by disabling the ROM BAR (by clearing bit 0).
>>
>> I'm agnostic ... anyone have any preferences?
>
> Well, given that sometimes the ROM is important, it seems like an
> error.  Really we should be smarter about re-allocating things as
> necessary...
>
> --
> Jesse Barnes, Intel Open Source Technology Center
>

I guess the easiest would be to silence the problem,
(but personally I don work that way)
So I opt for the second choice:
we could declare this to be a
bug, and fix it by disabling the ROM BAR (by clearing bit 0).

So If and when, I can test out a patch.

-- 
Justin P. Mattock
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