Not really, the sub-text I mentioned is just one of those kernel things that you 'just know' ;-). The problem is that people aren't born knowing it. Mostly in IOKit you don't have to worry about interrupt time as aside from Filters you never run at interrupt time, which is how this hole in the documentation came about. Godfrey At 16:44 -0500 01-11-12, Chris Edgington wrote:

The Filter is called on the primary hardware interrupt context. Very little of the system is available at this time. The IOLog doc says

that you can't run at interrupt time, the sub text is that you can't call it at hardware interrupt time, or in IOKit terms at Filter time. Does this help? Sure ... but I don't see the sub text that you mention in the docs I'm looking at, maybe there's a better source for documentation ... I'm referring to: <http://developer.apple.com/techpubs/macosx/Darwin/Reference/Kernel/I OLib/Functions/Functions.html>http://developer.apple.com/techpubs/maco sx/Darwin/Reference/Kernel/IOLib/Functions/Functions.html <Hopefully the link won't wrap - converted message to HTML to keep that from happening.>