From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: EdV@macrolink.com (Ed Vance)
Cc: linux-kernel@vger.kernel.org ('linux-kernel')
Subject: Re: PCI drivers - memory mapped vs. I/O ports
Date: Mon, 18 Mar 2002 20:32:09 +0000 (GMT) [thread overview]
Message-ID: <E16n3ne-0005xI-00@the-village.bc.nu> (raw)
In-Reply-To: <11E89240C407D311958800A0C9ACF7D13A7715@EXCHANGE> from "Ed Vance" at Mar 18, 2002 11:50:41 AM
> If a PCI device can be programmed equally well via I/O port space or memory
> space, what are the reasons to chose one space over the other when writing
> the driver?
mmio is posted on a PC i/o ports are not. That means you have to be more
careful but also means that
write
write
write
read
is a lot faster
next prev parent reply other threads:[~2002-03-18 20:16 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-03-18 19:50 PCI drivers - memory mapped vs. I/O ports Ed Vance
2002-03-18 20:32 ` Alan Cox [this message]
2002-03-18 20:36 ` Richard B. Johnson
2002-03-19 2:17 ` Jeff Garzik
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