Hi!
I'm writing a kext to control a USB->Ethernet chip under Mac OS X.
Structurally, it's similar to the USBCDCEthernetDriver example in that it's
derived from IOEthernetController and has the USB device as it's provider.
One of the things I ran into is that while it's possible to make lots of
synchronous DeviceRequest() calls from within the start() method of my
driver, I can't make them from within the enable() method, because the
enable() method is synchronized to the workloop gate, and apparently
synchronous DeviceRequest() calls result in a deadlock at that point.
I've considered making all my DeviceRequest() calls asynchronous, but there
are a *lot* of them (potentially over 20, if the device starts out in a
suspended state...) which need to be made to setup and enable this device,
and it's making for very messy and hard to maintain code, something I prefer
to avoid whenever possible. I'd like to find some mechanism which would
allow me to defer those device requests and make them all synchronously at
some later point.
As far as I can tell from my research, if I use runAction to defer the
sequence, then it's still going to block on my DeviceRequest() calls, so
that isn't a solution. Anyone know of a way to resolve this?
-->Steve Bennett
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