Date: Wed, 29 Aug 2007 13:12:32 -0500
From: Nathan Lynch <ntl@pobox.com>
To: Joachim Fenkes <fenkes@de.ibm.com>
Cc: LinuxPPC-Dev <linuxppc-dev@ozlabs.org>,
       LKML <linux-kernel@vger.kernel.org>, Paul Mackerras <paulus@samba.org>,
       Thomas Klein <tklein@de.ibm.com>,
       Jan-Bernd Themann <themann@de.ibm.com>,
       Christoph Raisch <raisch@de.ibm.com>,
       Stefan Roscher <stefan.roscher@de.ibm.com>
Subject: Re: [PATCH 2.6.23] ibmebus: Prevent bus_id collisions
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References: <200708291815.18197.fenkes@de.ibm.com>
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Hi-

Joachim Fenkes wrote:
> Previously, ibmebus derived a device's bus_id from its location code. The
> location code is not guaranteed to be unique, so we might get bus_id
> collisions if two devices share the same location code. The OFDT full_name,
> however, is unique, so we use that instead.

This is a userspace-visible change, but I guess it's unavoidable.
Will anything break?

Also, I dislike this approach of duplicating the firmware device tree
path in sysfs.  Are GX/ibmebus devices guaranteed to be children of
the same node in the OF device tree?  If so, their unit addresses will
be unique, and therefore suitable values for bus_id.  I believe this
is what the powerpc vio bus code does.

-
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