Yesterday, information became widely available that described possible stability issues (system crashes, hangs, etc.) when using an AGP video card under Linux in conjunction with an AMD Athlon processor. It was generally called a "bug" in the Athlon CPU.
More information is now available at <http://www.gentoo.org>, including an analysis of AMD's response. AMD's official response was posted to LKML, and is available at <http://www.geocrawler.com/lists/3/Linux/35/175/7626960/>. There is apparently some kind of bad interaction between the AGP GART ("Graphics Address Remapping Table", I think?), speculative reads performed by the Athlon processor, the memory mappings used by the kernel, and cache coherency. The details are beyond me, but the practical upshot appears to be that the wrong data ends up being written back to main memory at some point. I recommend reading the above LKML thread if you suspect you are affected by this issue. Information is still being uncovered, and it is not immediately clear how this occurs, what causes it, who is affected by it, and how to work around it. In particular, there is some uncertainty as to whether the "mem=nopentium" option actually prevents the problem, or merely makes it less likely to occur. -- Ben Scott <[EMAIL PROTECTED]> | The opinions expressed in this message are those of the author and do not | | necessarily represent the views or policy of any other person, entity or | | organization. All information is provided without warranty of any kind. | ***************************************************************** To unsubscribe from this list, send mail to [EMAIL PROTECTED] with the text 'unsubscribe gnhlug' in the message body. *****************************************************************
