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: Fri, 10 Aug 2007 19:58:43 +0200 [thread overview]
Message-ID: <6681fdad128303fc62c86c2345aa33a4@kernel.crashing.org> (raw)
In-Reply-To: <20070809212420.GD13921@localdomain>
>>> 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?
>
> Okay, then the change should be fine for maple.
Yes. Of course, as usual, testing is needed, yada yada.
>>> 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?
>
> Alright, well, maybe take it up with Ben when I post the patch for
> powermac, since that's where it could actually matter.
It should be fine on PowerMac as well -- all G5s use U3/U4,
the workaround is for certain older Apple bridge chips.
Segher
next prev parent reply other threads:[~2007-08-10 17:58 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
2007-08-09 21:24 ` Nathan Lynch
2007-08-10 17:58 ` Segher Boessenkool [this message]
2007-08-11 23:41 ` Benjamin Herrenschmidt
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