Linux: fire multiple URBs at once for split transfers

This results in a significant performance increase for bulk transfers
larger than 16kb, and fixes a bug where data would be spliced and mixed
between two simultaneously submitted transfers to the same endpoint.

It also allows isochronous transfers larger than 16kb to be submitted.

This commit also improves cancellation - the library now understands
what is going on.

1 files changed, 2 insertions, 0 deletions

diff --git a/libusb/libusbi.h b/libusb/libusbi.h
index 3cc33bf..c589ef6 100644
--- a/libusb/libusbi.h
+++ b/libusb/libusbi.h
@@ -283,6 +283,8 @@ struct usbi_os_backend {
 	size_t transfer_priv_size;
 
 	/* number of additional bytes for os_priv for each iso packet */
+	/* FIXME: linux can't use this any more. if other OS's cannot either,
+	 * then remove this */
 	size_t add_iso_packet_size;
 };