Date: Mon, 3 Sep 2007 21:01:24 +0200
From: Martin Mares <mj@ucw.cz>
To: dean gaudet <dean@arctic.org>
Cc: Robert Richter <robert.richter@amd.com>, Andi Kleen <ak@suse.de>,
       patches@x86-64.org, linux-kernel@vger.kernel.org
Subject: Re: [patch 5/5] x86: Set PCI config space size to extended for AMD Barcelona
Message-ID: <mj+md-20070903.190044.18705.albireo@ucw.cz>
References: <20070903081736.288288000@amd.com> <20070903081736.805623000@amd.com> <Pine.LNX.4.64.0709030930150.3502@twinlark.arctic.org>
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Hi!

> it's so very unfortunate the PCI standard has no feature bit to indicate 
> the presence of ECS.
> 
> FWIW in my testing on a range of machines spanning 7 or 8 years i could 
> read config space reg 256... and get 0xffffffff when the device didn't 
> support ECS, and get valid data when the device did support ECS... granted 
> there may be some system out there which behaves really badly when you do 
> this.
> 
> perhaps someone could write a userspace program and test that concept on a 
> far wider range of machines.

If you want to experiment with this in user space, it's easy to write
a couple of access functions for the libpci in pciutils. (Patches welcome,
as usually :) )

				Have a nice fortnight
-- 
Martin `MJ' Mares                          <mj@ucw.cz>   http://mj.ucw.cz/
Faculty of Math and Physics, Charles University, Prague, Czech Rep., Earth
God is real, unless declared integer.
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