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As most of the AC97's are in South Bridges or MCP chips I figured you might find something worthwhile in one of those two places for your issue and possibly also other issues you did not know you had yet.
One of the most common Audio problems other than that is a NIC or USB controller double or triple stacked with one IRQ for two or three of those devices assigned by BIOS. I ended up running an Enterprise 2.4.21+ kernel with both RedHat and Mandrake 9.1 and strangely enough that seemed to handle double stacked IRQs better(on both P4 and Barton boxes). This especially works if you have a large amount of RAM (over .75 GIG *including* Video RAM in some cases). This fixed video hangs, sound farts and dropouts, LAN barfings, and a whole host of issues.
It would appear that kernel 2.4.21 and up also handle power management and PCI device handling better than kernels through 2.4.20-- been talking to a lot of folks about this set of issues, and the 2.6tree has many more fixes for this but that is not an official release and will not be until later this year (probably fourth quarter now that Linus is working full tiem on kernel). Quite a few folks that ended up compiling kernels started with 2.4.21 or 2.5 (beta) trees and got a lot of issues suddenly resolved. And ACPI and APIC seem to relate intimately to sound on boards that have stacked IRQs. Most modern boards, unfortuantely, DO have this problem.
I will alos suggest one other general idea-- artsd likes real time access to sound and on very modern boards it is not getting this (for stacked IRQ handling reasons). ALSA is much more tolerant of non-real-time sound and can run with OSS drivers. So, when you have a very modern board, not only do you need mfr of chipset drivers, plus non-real-time sound modules working, you need a very modern kernel to let modern power management and PCI device mgt work right.
Sometimes the first two alone suffice, but for the very latest nForces the mfr drivers and a custom kernel soemtimes end up being the best ofption plus the use of multimedia apps that work with ALSA and OSS and which avoid ARTS.
Good Luck.
John Danielson.
