From: Anders Gustafsson <andersg@0x63.nu>
To: Dave Jones <davej@codemonkey.org.uk>,
torvalds@osdl.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] XBox Gaming System subarchitecture.
Date: Mon, 14 Jul 2003 16:54:29 +0200 [thread overview]
Message-ID: <20030714145429.GD20708@h55p111.delphi.afb.lu.se> (raw)
In-Reply-To: <20030714142838.GA29413@suse.de>
On Mon, Jul 14, 2003 at 03:28:38PM +0100, Dave Jones wrote:
> > The real patch contains cleaned up HZ-ifdefs.
>
> good good..
Testing it an extra time now.
> > Or as Christoph answered: "Oh well, stupid crappy hardware..."
>
> That's a possibility, but if that were the case, I'd expect other things
> also to start randomly failing. It's unclear to me how -O2 would make
> a hardware bug more aparent. If it did so, that would also mean you'd
> have to ensure all your userspace was similarly compiled, which sounds
> very suspect. It's just a celeron based PC with nvidia nforce chipset right ?
> If that combination caused such problems, I'd expect to see the
> occasional problem report from non-Xbox regular home-built PC users too.
It only happens when paging is off. Hence no problem as soon as the kernel
is up and running. -O2 changes the memory-access patterns so it is quite
possible that it would expose hardware bugs.
> Might be one worth picking over on the gcc lists if you can identify
> which part gets miscompiled ?
>
> Tried different versions of binutils too ?
On 1.0 xboxes it works with any gcc with or without optimizations on.
On 1.1+ xboxen it does NOT work with 2.95, -O0 or -O2. But with 3.2.2-3.3 it
is known to work with -O0.
It's was not easy to localize the crashes. Cos adding more code for
debugging moves the point where it crashes around. However it does crash
reading from memory. A prefectly valid address. That it just a few
instructions earlier had written and read from.
--
Anders Gustafsson - andersg@0x63.nu - http://0x63.nu/
next prev parent reply other threads:[~2003-07-14 14:43 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-07-14 12:49 [PATCH] XBox Gaming System subarchitecture Anders Gustafsson - xbox patch monkey
2003-07-14 13:59 ` Dave Jones
2003-07-14 14:21 ` Anders Gustafsson
2003-07-14 14:28 ` Dave Jones
2003-07-14 14:54 ` Anders Gustafsson [this message]
2003-07-14 15:04 ` [CORRECT PATCH] " Anders Gustafsson
2003-07-15 12:39 ` [PATCH] " Eric W. Biederman
2003-07-15 12:51 ` Anders Gustafsson
2003-07-15 17:48 ` Mike Fedyk
2003-07-14 14:32 ` Jeff Garzik
2003-07-14 16:12 ` Linus Torvalds
2003-07-14 16:45 ` Anders Gustafsson
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