From: Prarit Bhargava <prarit@redhat.com>
To: Bjorn Helgaas <bhelgaas@google.com>
Cc: Rolf Eike Beer <eike-kernel@sf-tec.de>,
Matthew Wilcox <matthew@wil.cx>, Don Dutile <ddutile@redhat.com>,
James Paradis <jparadis@redhat.com>,
linux-pci@vger.kernel.org, mstowe@redhat.com,
jbarnes@virtuousgeek.org
Subject: Re: [PATCH] pci: Workaround Stratus broken PCIE hierarchy
Date: Tue, 15 Nov 2011 13:25:30 -0500 [thread overview]
Message-ID: <4EC2AE9A.1030208@redhat.com> (raw)
In-Reply-To: <CAErSpo5=YFNMcDt59JU2HQJV2EZpy1khLLCxyPAf49w8m4=kOA@mail.gmail.com>
Bjorn,
>
> Is this problem a regression? If so, what commit caused it?
> f07852d6442, which introduced only_one_child()?
That's a tough question to answer. AFAICT the broken (HARDWARE broken) Stratus systems only enumerated properly by chance. Did they work prior to f07852d6? From what jparadis told me, yes. Is it a regression? ... depends on how you look at it.
>
> Does Windows work on this system?
I don't know. jparadis? Any clue?
>
> Is this something that could be fixed by a firmware upgrade? If so,
> is there a Stratus/NEC bug report?
Hmmm, the idea of a FW upgrade somehow fixing this never occurred to me. jparadis? Is that possible?
>
> Is there a Red Hat bugzilla URL you could include?
Only happens upstream.
>
> What bad things would happen if we just turned on this
> Stratus-specific behavior all the time on all systems? It looks like
> f07852d6442 is basically an optimization that makes pci_scan_slot()
> faster, so I assume one effect would be to slow down PCI enumeration
> for everybody. By how much?
Not a huge amount -- estimated lt 0.5 seconds on this Stratus system. As for other systems, it obviously depends on how complicated the PCIE hierarchy is.
P.
next prev parent reply other threads:[~2011-11-15 18:26 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-10 14:00 [PATCH] pci: Workaround Stratus broken PCIE hierarchy Prarit Bhargava
2011-11-10 14:31 ` Matthew Wilcox
2011-11-10 16:50 ` Don Dutile
2011-11-11 17:41 ` James Paradis
2011-11-11 19:13 ` Don Dutile
2011-11-11 20:29 ` Bjorn Helgaas
2011-11-11 20:35 ` Don Dutile
2011-11-14 14:44 ` Prarit Bhargava
2011-11-14 18:14 ` Matthew Wilcox
2011-11-14 19:50 ` Prarit Bhargava
2011-11-15 20:16 ` Matthew Wilcox
2011-11-15 15:56 ` Prarit Bhargava
2011-11-15 16:08 ` Rolf Eike Beer
2011-11-15 18:14 ` Bjorn Helgaas
2011-11-15 18:25 ` Prarit Bhargava [this message]
2011-11-15 21:08 ` James Paradis
2011-11-15 21:52 ` Myron Stowe
2011-11-15 22:14 ` James Paradis
2011-11-15 20:15 ` Matthew Wilcox
2011-11-16 16:53 ` Prarit Bhargava
2011-11-17 0:18 ` Prarit Bhargava
2011-11-15 21:53 ` James Paradis
2011-11-15 22:27 ` James Paradis
2011-11-15 23:07 ` Don Dutile
-- strict thread matches above, loose matches on Subject: below --
2012-04-25 17:56 Prarit Bhargava
2012-04-25 23:35 ` Bjorn Helgaas
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