Date: Tue, 05 Feb 2002 10:17:57 -0500 From: Aniruddha Bohra <bohra@cs.rutgers.edu> To: freebsd-questions@freebsd.org Subject: Does this affect FreeBSD? Message-ID: <3C5FF7A5.7000805@cs.rutgers.edu>
next in thread | raw e-mail | index | archive | help
Hi
Came across this while trying to find why my computer spontaneously
reboots.
Apparently there is some bug/feature in the AMD Athlon chip which
interacts with
the graphics card to cause the reboot. Does this affect the FreeBSD
systems as well?
http://www.theregister.co.uk/content/3/23749.html
---Article Snip
Daniel concludes that neither side is guilty; that it isn't an AMD
bug, more a feature; but he also recommends that kernel hackers
find a new problem to this particular situation. It appears that the
GART (Graphics Address Remapping Table) which feeds the AGP
card with system memory isn't cache coherent. Although both Linux
(and apparently Windows 2000) expect it to be.
The GART lays out memory for the AGP card in a contiguous block,
but the real memory that's being addressed. of course, lies all over
the place - having been paged out in 4k blocks from main system
memory. Intel added 4MB pages, and the temporary workaround for
both Linux and Windows 2000 is to disable the 4MB page option.
AMD concludes:- "Our conclusion is that the operating system is
creating coherency problems within the system by creating cacheable
translation to AGP GART-mapped physical memory...
When the cache-line eviction occurs the stale data written to
physical memory has fatal side effects."
To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-questions" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?3C5FF7A5.7000805>