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I'm working on an installer in OS X that installs an IOKit driver for a USB device, and I'm trying to get it to not require a restart at the end. The installer installs the driver correctly and rebuilds the kext cache, and after it runs, if I unplug and replug the USB device, it correctly loads the new driver and everything works fine.

However, I don't want to require the user to physically unplug the device in order for the new driver to load. There's got to be a way to get OS X to load the new driver programmatically - in effect simulate the device being unplugged and plugged back in again, or something similar. How would I go about doing this? So far, hours of Googling has turned up nothing, so any help will be greatly appreciated!

Bri Bri
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  • I'd try looking at the code that gets run when you eject a USB mass storage device — I'm not sure if there's corresponding USB traffic or if it just tells the USB subsystem to ignore the port until a physical unplug. In the former case (a "USB eject" message), there might not be an easy way to "un-eject" apart from power-cycling or a USB reset, both of which might be problematic for other USB devices. But hopefully that's somewhere to start looking. – tc. Oct 08 '12 at 19:27
  • I read about something called `pmount` which can unmount more arbitrary USB devices, but I don't know if that includes your device. The only big downside is that it doesn't come with OS X by default. – rien333 Oct 08 '12 at 20:45
  • I'm fairly certain you can't do this directly from user space. However, in the kernel, you could try calling terminate() on the existing client that's hogging the device. – pmdj Oct 09 '12 at 15:26

2 Answers2

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IOUSBDeviceInterface187::USBDeviceReEnumerate() will do what you want. The only hitch is that to find all of the devices of interest and call this on them manually with IOServiceGetMatchingServices().

/*!
@function USBDeviceReEnumerate
@abstract   Tells the IOUSBFamily to reenumerate the device.
@discussion This function will send a terminate message to all clients of the IOUSBDevice (such as 
            IOUSBInterfaces and their drivers, as well as the current User Client), emulating an unplug 
            of the device. The IOUSBFamily will then enumerate the device as if it had just 
            been plugged in. This call should be used by clients wishing to take advantage 
            of the Device Firmware Update Class specification.  The device must be open to use this function. 
@availability This function is only available with IOUSBDeviceInterface187 and above.
@param      self Pointer to the IOUSBDeviceInterface.
@param      options A UInt32 reserved for future use. Ignored in current implementation. Set to zero.
@result     Returns kIOReturnSuccess if successful, kIOReturnNoDevice if there is no connection to an IOService,
            or kIOReturnNotOpen if the device is not open for exclusive access.
*/

IOReturn (*USBDeviceReEnumerate)(void *self, UInt32 options);

Look in IOKit/usb/IOUSBLib.h

Ted Middleton
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Take a look at diskutil, and especially the mount and unmount options. Those will softwarematically eject and mount devices. You can use diskutil list to get a list of all the currently mounted devices. If you need more info on diskutil, just look at the man page.

rien333
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  • Unfortunately this device isn't a disk, it's a human interface device, so as far as I know diskutil won't help. – Bri Bri Oct 08 '12 at 19:56