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[H]ardNews 9th Edition
AMD Folding Issues Revisited:
Matt "CIWS" Waters sends me news that AMD has posted an errata concerning an issue we posted information on regarding Athlon64 processors hard locking while running the Folding@Home client a while back. This is what Matt had to say:
Remember a few months back where certain AMD CPUs were causing hard locks with the Folding client ? AMD did get with the Stanford folks and help them produce a workaround to the issue that was incorporated into the newer Folding client core and the problem went away. Well there has apparently been an Errata issued (rather quietly) on the problem and is now shown in this document on the AMD website. It's errata # 105. So thanks to AMD for working the problem and finding out what had been going on all of those months.
From the AMD Revision Guide:
A processor deadlock may occur under the following conditions: A 128-bit store operation (MOVUPS, MOVUPD, MOVDQU) occurs to a cacheable memory type. The store is misaligned across two cache lines such that the upper 8 bytes span a cache line boundary. The store has retired but not yet written the data cache. The store is followed by two other load or store operations to the same cache index as the second half of the misaligned store store (i.e., bits 11:6 are the same).
Potential Effect on System: In the unlikely event that the above conditions occur the system may hang.
Suggested Workaround: None
Fix Planned: Yes
You can download the whole Revision Guide #25759 rev 3.25 (right click, save as) for AMD Athlon™ 64 and AMD Opteron™ processors in .PDF form here.