tree add71b10dc2275c98d3439fe3756829c2ec0afc9
parent 27c7acf22047fbe4ec4cc36b7c2610dba227697c
author Johan Hovold <jhovold@gmail.com> 1273096693 +0200
committer Greg Kroah-Hartman <gregkh@suse.de> 1274386902 -0700

USB: serial: remove multi-urb write from generic driver

Remove multi-urb write from the generic driver and simplify the
prepare_write_buffer prototype:

	int (*prepare_write_buffer)(struct usb_serial_port *port,
						void *dest, size_t size);

The default implementation simply fills dest with data from port write
fifo but drivers can override it if they need to process the outgoing
data (e.g. add headers).

Turn ftdi_sio into a generic fifo-based driver, which lowers CPU usage
significantly for small writes while retaining maximum throughput.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>