Came across this KB article while looking up some other info in the Microsoft KB:
KB920918 - An IDE device runs in PIO mode instead of in DMA mode after you update the firmware for the device in Windows XP
Sounds familiar, eh? Well, according to Microsoft, it’s a bug on their end (as if we didn’t know), and they have an updated version of atapi.sys that fixes the problem, available as a hotfix.
However, the KB article also notes that this hotfix has not been fully tested, so it is available only upon request. Now, there have been people who have requested this hotfix from Microsoft and then subsequently posted it online at this repository if you want try it without saying hello first to the friendly folks of Microsoft Support. Just be mindful that this is something that Microsoft has not publicly made available yet (and like the hundreds of other “minor” hotfixes that Microsoft produces on its QFE branch, its first public release will probably be as a part of SP3, which is still a ways off on the horizon).
One final note. You also have the option to download the newer KB934205 (also not publicly released, but can be found at the repository noted above) instead. KB934205 contains a newer version of atapi.sys than the version found in the KB920918 hotfix, so in a sense, the KB920918 is “included” in and superseded by KB934205.
And while we’re on the topic of Microsoft hotfixes, I suppose I should point out that IMAPIv2 (KB932716) was released last Tuesday. This brings native DVD recording to XP, to bring XP to parity with Vista in that particular department, but since I’d imagine that very few people here actually use the built-in Windows recording functionality, this will be of limited importance to this particular audience.
And yes, I know, technically, this would belong more in a software forum, except that Womble’s DMA guide is in this forum and also because more people actually step foot in hardware than in software…