From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Matt Sealey <matt@genesi-usa.com>
Cc: linuxppc-dev@ozlabs.org, Marian Balakowicz <m8@semihalf.com>
Subject: Re: PCI IO range limitation
Date: Sat, 30 Jun 2007 09:14:59 +1000 [thread overview]
Message-ID: <1183158899.5521.377.camel@localhost.localdomain> (raw)
In-Reply-To: <46853CA2.2040203@genesi-usa.com>
> Define "legacy device"? What should that entail? You mean like mapping
> most of those registers to the first couple of kilobytes of "IO"?
Anything that hard-decodes IOs in the low ISA range yes. That includes
VGA video cards.
> If they're just left as their own on their own as PCI devices, why would
> it matter what the window was?
Because quite a few of those things hard decodes (can't be moved around,
so -have- to be able to generate cycles to those low addresses to hit
them) and sometimes don't even fully decode the 32 bits addresses
(though that's more rare).
For example, a VGA video card in text mode hard decodes both IO and
Memory at the legacy VGA ranges.
Ben.
next prev parent reply other threads:[~2007-06-29 23:15 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-06-28 10:20 PCI IO range limitation Marian Balakowicz
2007-06-28 17:43 ` Benjamin Herrenschmidt
2007-06-28 23:38 ` Matt Sealey
2007-06-29 0:13 ` Benjamin Herrenschmidt
2007-06-29 17:08 ` Matt Sealey
2007-06-29 23:14 ` Benjamin Herrenschmidt [this message]
2007-07-03 9:24 ` Marian Balakowicz
2007-07-03 11:13 ` Benjamin Herrenschmidt
2007-07-06 13:37 ` Marian Balakowicz
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