From: Andi Kleen <andi@firstfloor.org>
To: "David P. Reed" <dpreed@reed.com>
Cc: linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: RFC: outb 0x80 in inb_p, outb_p harmful on some modern AMD64 with MCP51 laptops
Date: Fri, 07 Dec 2007 11:44:57 +0100 [thread overview]
Message-ID: <p733auekcly.fsf@bingen.suse.de> (raw)
In-Reply-To: <475879CD.9080006@reed.com> (David P. Reed's message of "Thu\, 06 Dec 2007 17\:38\:05 -0500")
"David P. Reed" <dpreed@reed.com> writes:
>
> ANy help/suggestions?
Use a variable for the port and and do a early quirk to change
the port to something safe on your chipset?
Ok there might be code using outb_p() before the early quirks,
but should be possible to find using instrumentation.
Also the port assignment might not be chipset specific, but BIOS
specific, then you would need to match the DMI identifier. The
disadvantage of that is that there are usually other BIOS
with other identifiers but the same problem around.
> Changing the delay instruction sequence from the outb to short jumps
> might be the safe thing. But Linus, et al. may have experience with
> that on other architectures like older Pentiums etc.
I don't think that makes sense to do on anything modern. The trouble
is that the jumps will effectively execute near "infinitely fast" on any
modern CPU compared to the bus. But the delay really needs to be something
that is about IO port speed. Ok in theory you could try to measure
a outb using RDTSC and then use udelay, but first you would need
a safe port for that already and then RDTSC is not necessarily constant.
-Andi
next prev parent reply other threads:[~2007-12-07 10:45 UTC|newest]
Thread overview: 125+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-06 22:38 RFC: outb 0x80 in inb_p, outb_p harmful on some modern AMD64 with MCP51 laptops David P. Reed
2007-12-07 0:15 ` Alan Cox
2007-12-07 10:44 ` Andi Kleen [this message]
2007-12-07 14:50 ` David P. Reed
2007-12-05 11:10 ` Pavel Machek
2007-12-08 0:21 ` Andi Kleen
2007-12-07 14:54 ` Andi Kleen
2007-12-07 15:43 ` Rene Herman
2007-12-07 16:28 ` Rene Herman
2007-12-11 0:31 ` H. Peter Anvin
2007-12-11 5:53 ` H. Peter Anvin
2007-12-07 16:04 ` Alan Cox
2007-12-07 16:31 ` Andi Kleen
2007-12-07 17:19 ` Alan Cox
2007-12-07 18:45 ` Rene Herman
2007-12-07 18:42 ` Alan Cox
2007-12-07 19:25 ` Rene Herman
2007-12-07 21:45 ` Alan Cox
2007-12-08 19:25 ` David P. Reed
2007-12-08 19:50 ` Andi Kleen
2007-12-08 20:47 ` David P. Reed
2007-12-08 21:04 ` Alan Cox
2007-12-08 20:26 ` Alan Cox
2007-12-11 5:58 ` H. Peter Anvin
2007-12-09 5:04 ` Rene Herman
2007-12-09 13:22 ` Pavel Machek
2007-12-11 15:14 ` Lennart Sorensen
2007-12-09 12:54 ` Pavel Machek
2007-12-09 13:41 ` Dr. David Alan Gilbert
2007-12-09 15:54 ` Ondrej Zary
2007-12-09 16:59 ` Andi Kleen
2007-12-09 21:25 ` Pavel Machek
2007-12-09 22:29 ` Alan Cox
2007-12-09 23:22 ` Pavel Machek
2007-12-10 12:02 ` Alan Cox
2007-12-10 4:17 ` Rene Herman
2007-12-10 11:30 ` Krzysztof Halasa
2007-12-10 12:08 ` Rene Herman
2007-12-10 18:02 ` Ondrej Zary
2007-12-11 1:10 ` David Newall
2007-12-11 1:25 ` H. Peter Anvin
2007-12-11 1:42 ` David Newall
2007-12-11 1:46 ` H. Peter Anvin
2007-12-11 1:51 ` H. Peter Anvin
2007-12-11 7:40 ` Paul Rolland
2007-12-11 9:50 ` Rene Herman
2007-12-11 12:08 ` David Newall
2007-12-11 13:16 ` Rene Herman
2007-12-11 13:32 ` Paul Rolland
2007-12-11 14:15 ` Rene Herman
2007-12-11 15:28 ` Rene Herman
2007-12-11 15:37 ` Paul Rolland
2007-12-11 15:53 ` Rene Herman
2007-12-11 16:58 ` David P. Reed
2007-12-11 17:01 ` Rene Herman
2007-12-11 17:05 ` H. Peter Anvin
2007-12-11 17:32 ` Alan Cox
2007-12-11 19:19 ` David P. Reed
2007-12-11 19:36 ` Pavel Machek
2007-12-11 20:16 ` Alan Cox
2007-12-11 20:27 ` linux-os (Dick Johnson)
2007-12-11 20:34 ` Rene Herman
2007-12-11 21:03 ` David P. Reed
2007-12-11 23:56 ` David P. Reed
2007-12-12 13:11 ` linux-os (Dick Johnson)
2007-12-12 16:12 ` Alan Cox
2007-12-14 14:33 ` Ingo Molnar
2007-12-16 21:26 ` Pavel Machek
2007-12-17 0:02 ` Alan Cox
2007-12-17 0:03 ` Alan Cox
2007-12-17 0:28 ` Pavel Machek
2007-12-17 14:42 ` Ingo Molnar
2007-12-27 10:39 ` Pavel Machek
2007-12-12 19:42 ` Attitude problems David P. Reed
2007-12-12 20:31 ` linux-os (Dick Johnson)
2007-12-14 16:01 ` linux-os (Dick Johnson)
2007-12-11 16:32 ` RFC: outb 0x80 in inb_p, outb_p harmful on some modern AMD64 with MCP51 laptops John Stoffel
2007-12-11 16:40 ` Rene Herman
2007-12-11 13:50 ` David Newall
2007-12-11 14:14 ` Rene Herman
2007-12-11 14:25 ` Alan Cox
2007-12-12 22:18 ` David Newall
2007-12-12 23:00 ` Alan Cox
2007-12-13 13:13 ` David P. Reed
2007-12-13 13:21 ` Alan Cox
2007-12-14 1:50 ` David P. Reed
2007-12-14 15:16 ` Alan Cox
2007-12-11 15:41 ` linux-os (Dick Johnson)
2007-12-11 16:30 ` Andi Kleen
2007-12-11 16:50 ` Rene Herman
2007-12-11 17:00 ` David P. Reed
2007-12-11 17:04 ` Rene Herman
2007-12-11 17:27 ` Rene Herman
2007-12-11 19:18 ` Pavel Machek
2007-12-11 19:16 ` Pavel Machek
2007-12-11 19:59 ` Rene Herman
2007-12-11 19:59 ` Rene Herman
2007-12-11 20:00 ` Rene Herman
2007-12-11 20:00 ` Rene Herman
2007-12-12 20:07 ` More info on port 80 symptoms on MCP51 machine David P. Reed
2007-12-12 20:26 ` Rene Herman
2007-12-12 20:37 ` David P. Reed
2007-12-12 20:58 ` Rene Herman
2007-12-12 21:01 ` Alan Cox
2007-12-12 21:12 ` H. Peter Anvin
2007-12-12 21:29 ` Alan Cox
2007-12-15 22:34 ` Allen Martin
2007-12-15 22:46 ` H. Peter Anvin
2007-12-16 0:46 ` David P. Reed
2007-12-12 21:05 ` H. Peter Anvin
2007-12-14 22:05 ` Chuck Ebbert
2007-12-15 7:22 ` Rene Herman
2007-12-11 13:14 ` RFC: outb 0x80 in inb_p, outb_p harmful on some modern AMD64 with MCP51 laptops Alan Cox
2007-12-11 13:32 ` Andi Kleen
2007-12-11 13:47 ` Pavel Machek
2007-12-11 13:50 ` Andi Kleen
2007-12-14 13:33 ` Ingo Molnar
2007-12-11 6:54 ` Rene Herman
2007-12-11 17:01 ` H. Peter Anvin
[not found] <fa./27SNSh+L5T3iqFNPdHClEu+yT0@ifi.uio.no>
2007-12-07 0:23 ` Robert Hancock
2007-12-07 5:09 ` Rene Herman
2007-12-07 5:54 ` David P. Reed
2007-12-07 7:17 ` Rene Herman
2007-12-07 7:34 ` Rene Herman
2007-12-07 10:49 ` Andi Kleen
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