Collect an information about suspended USB devices via IOUSBDeviceInterface245
I'm trying to get some information (such a product name) via IOUSBDeviceInterface245
(from IOKit on Mac OS X):
io_iterator_t iterator;
io_object_t usb_device
SInt32 score = 0;
kern_return_t kr = IOServiceGetMatchingServices(kIOMasterPortDefault,
IOServiceNameMatching("AppleUSBOHCI"),
&iterator);
IOCFPlugInInterface **plugin_interface = NULL;
IOUSBDeviceInterface245 **usb_interface = NULL;
// ...
// enumerate devices (usb_device = IOIteratorNext(iterator))
// ...
IOReturn return_code = IOCreatePlugInInterfaceForService(usb_device,
kIOUSBDeviceUserClientTypeID,
kIOCFPlugInInterfaceID,
&plugin_interface,
&score);
HRESULT h_result = (*pluginInterface)->QueryInterface(pluginInterface,
CFUUIDGetUUIDBytes(kIOUSBDeviceInterfaceID245),
(LPVOID)&usb_interface);
IODestroyPlugInInterface(pluginInterface);
UInt8 product_string_index;
return_code = (*usb_interface)->USBGetProductStringIndex(usb_interface,
&product_string_index);
// Next, getting a product string by string's index. To do so, we need to send
// IOUSBDevRequest (with type "kUSBRqGetDescriptor") to the current USB-device.
// Code bellow - is a pseudocode:
char *product_name = malloc(128);
get_string_by_index(usb_interface, product_string_index, product_string, 128);
This code is working well for all working-now devices, but it doesn't working for suspended ("sleeping")
devices (product_name
is just a blank string).
But, if I using this code:
Code #2 CFMutableDictionaryRef child_properties = CFDictionaryCreateMutable(NULL, 0,
NULL,NULL);
kern_return_t kr;
io_service_t io_service;
// iterator = iterator for "AppleUSBOHCI" or "AppleUSBEHCI" services
while((io_service = IOIteratorNext(iterator))) {
io_iterator_t children_iterator;
kernel_return = IORegistryEntryGetChildIterator(io_serv开发者_Python百科ice, kIOServicePlane,
&children_iterator);
io_registry_entry_t child;
while((child = IOIteratorNext(children_iterator))) {
// Create a CFDictionary with usb-device's properties
IORegistryEntryCreateCFProperties(child, &child_properties,
kCFAllocatorDefault,
kNilOptions);
NSLog(@"%@",[(NSDictionary*)child_properties valueForKey:@"USB Product Name"]);
}
}
that's working for all devices at all (I don't know why).
I tried to wakeup a suspended devices by this code (using with the code #1):
(*usb_interface)->USBDeviceSuspend(usb_interface, false);
but it's changed nothing.
One thing that I noticed - the code #1 is fully working for all properties of sleeping devices, except string values (which getting by string's index).
UPDATE:
So, my question is how can I unsuspend a device for using with the first code block? Thank you.You can't read the string from a suspended device (as in code #1) as it is read directly from the device (which can't respond, as it is suspended). To read these directly, you will need to unsuspend the device first (which may be a bad idea if it was suspended by a driver, also, remember to check for success)
If you want to read the standard strings, use the second code block (which reads the properties, which were already fetched from the device)
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