1USB_GET_DESCRIPTOR(9)            USB Core APIs           USB_GET_DESCRIPTOR(9)
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NAME

6       usb_get_descriptor - issues a generic GET_DESCRIPTOR request
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SYNOPSIS

9       int usb_get_descriptor(struct usb_device * dev, unsigned char type,
10                              unsigned char index, void * buf, int size);
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ARGUMENTS

13       dev
14           the device whose descriptor is being retrieved
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16       type
17           the descriptor type (USB_DT_*)
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19       index
20           the number of the descriptor
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22       buf
23           where to put the descriptor
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25       size
26           how big is “buf”?
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CONTEXT

29       !in_interrupt ()
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DESCRIPTION

32       Gets a USB descriptor. Convenience functions exist to simplify getting
33       some types of descriptors. Use usb_get_string or usb_string for
34       USB_DT_STRING. Device (USB_DT_DEVICE) and configuration descriptors
35       (USB_DT_CONFIG) are part of the device structure. In addition to a
36       number of USB-standard descriptors, some devices also use
37       class-specific or vendor-specific descriptors.
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39       This call is synchronous, and may not be used in an interrupt context.
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RETURN

42       The number of bytes received on success, or else the status code
43       returned by the underlying usb_control_msg call.
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46Kernel Hackers Manual 3.10         June 2019             USB_GET_DESCRIPTOR(9)
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