From: Gabriel Paubert <paubert@iram.es>
To: Gary Thomas <gary@mlbassoc.com>
Cc: Linux PPC Development <linuxppc-dev@ozlabs.org>
Subject: Re: Change in PCI behaviour
Date: Mon, 22 Nov 2010 11:37:17 +0100 [thread overview]
Message-ID: <20101122103717.GA11649@iram.es> (raw)
In-Reply-To: <4CE69AF6.6090408@mlbassoc.com>
On Fri, Nov 19, 2010 at 08:42:46AM -0700, Gary Thomas wrote:
> In this case, note that PCI device 0000:00:0c.0 is at 0xc0000000.
> This causes problems because it's a truly stupid device that does
> not work properly at PCI [relative] address 0x00000000. It simply
> does not respond at that address. Pick anywhere else and it will
> work fine!
Yes, but it was one upon a time in the PCI spec that setting the
a base register to 0 should disable the corresponding decoder.
I don't know whether this has changed (I actually never had the
final PCI spec, only drafts). However I once had a device who
actually did not disable base addresses set to zero and this was
described as a bug in its (numerous) errata. This also caused
a lot of mayhem since in some versions/configurations it used
up to 64kB of PCI I/O space (especially fun on x86...).
Gabriel
prev parent reply other threads:[~2010-11-22 10:42 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-19 15:42 Change in PCI behaviour Gary Thomas
2010-11-19 21:46 ` Benjamin Herrenschmidt
2010-11-21 17:59 ` Gary Thomas
2010-11-22 10:01 ` Gary Thomas
2010-11-22 20:26 ` Benjamin Herrenschmidt
2010-11-23 14:44 ` Gary Thomas
2010-12-04 12:49 ` Gary Thomas
2010-12-04 21:07 ` Benjamin Herrenschmidt
2010-11-22 10:37 ` Gabriel Paubert [this message]
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