The Linux-USB Host Side API | ||
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request block being initialized. until usb_sg_wait returns, treat this as a pointer to an opaque block of memory,
the usb device that will send or receive the data
endpoint "pipe" used to transfer the data
polling rate for interrupt endpoints, in frames or (for high speed endpoints) microframes; ignored for bulk
scatterlist entries
how many entries in the scatterlist
how many bytes to send from the scatterlist, or zero to send every byte identified in the list.
SLAB_* flags affecting memory allocations in this call
Returns zero for success, else a negative errno value. This initializes a scatter/gather request, allocating resources such as I/O mappings and urb memory (except maybe memory used by USB controller drivers).
The request must be issued using usb_sg_wait, which waits for the I/O to complete (or to be canceled) and then cleans up all resources allocated by usb_sg_init.
The request may be canceled with usb_sg_cancel, either before or after usb_sg_wait is called.
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usb_bulk_msg | Up | usb_sg_wait |