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From: Segher Boessenkool <segher@kernel.crashing.org>
To: Nathan Lynch <ntl@pobox.com>
Cc: linuxppc-dev@ozlabs.org, Paul Mackerras <paulus@samba.org>,
	David Gibson <david@gibson.dropbear.id.au>
Subject: Re: [RFC/PATCH] remove gratuitous reads from maple pci config space methods
Date: Thu, 9 Aug 2007 12:40:52 +0200	[thread overview]
Message-ID: <40561246eaa06210a2a607aa7ed67b02@kernel.crashing.org> (raw)
In-Reply-To: <20070809041632.GA13921@localdomain>

>> It might be worth checking that there isn't a particular reason for
>> these.  Just because posting writes are forbidden doesn't mean a
>> particular bridge won't screw it up...
>
> Well, I had already checked with Ben, who wrote the code, and my
> understanding is that the reads are intended to work around some
> misbehaving Apple bridges,

None of the PCI interfaces on the U3 or U4 bridges have that
problem as far as I know.  I think the workaround was copied
from code for older Apple bridges?

> but that a sync after the write (implied by
> releasing pci_lock in the generic pci code) should suffice for those.

I don't see how a sync could help here at all, not more than
an eieio anyway?


Segher

  parent reply	other threads:[~2007-08-09 10:40 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-08-09  0:50 [RFC/PATCH] remove gratuitous reads from maple pci config space methods Nathan Lynch
2007-08-09  0:55 ` Benjamin Herrenschmidt
2007-08-09  1:04   ` Nathan Lynch
2007-08-09  1:14     ` Benjamin Herrenschmidt
2007-08-09 20:03     ` Olof Johansson
2007-08-09  3:05 ` David Gibson
2007-08-09  4:16   ` Nathan Lynch
2007-08-09  4:18     ` David Gibson
2007-08-09 10:40     ` Segher Boessenkool [this message]
2007-08-09 21:24       ` Nathan Lynch
2007-08-10 17:58         ` Segher Boessenkool
2007-08-11 23:41           ` Benjamin Herrenschmidt

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