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Re: USB DeviceRequest

Hi Joe,

I don't know what the latest is with USB development, but I had to do this a couple of years ago. I must say first that you should really try and figure out if you can do whatever you need to asynchronously, it is *highly* recommended by Apple.

The issue here is that there is only one workloop per USB controller. If you sleep/delay/whatever on the USB workloop, you stop everything.

What I did was create an IOSyncer object (check out Darwin sources - xnu/iokit/Drivers/platform/drvApplePMU/IOPMUADBController.cpp for an example of how to use this), which for whatever reason, allows the USB workloop to continue working while your driver waits.

-- John


Is it safe to call USB device manager synchronously?
Can I use IOCommandGate to issue IOUSBDevice_>DeviceRequest?
When I tried to send a device request in my IOCommandGate Action,
the request will be implemented but I don't get an IOReturn and the driver will hang for ever...Any suggestions will be appreciated!!!! 
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 >USB DeviceRequest (From: Joe Maloof <email@hidden>)



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