Commit 4b8e0795 authored Apr 12, 2021 by Johan Hovold

USB: serial: io_ti: document reason for drain delay



Document that the device line-status register doesn't tell when the
transmitter shift register has emptied and that this is why the
one-character drain delay is needed.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

parent 8674cabe

drivers/usb/serial/io_ti.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -2590,6 +2590,10 @@ static int edge_port_probe(struct usb_serial_port *port)
		if (ret)
		goto err;

		/*
		* The LSR does not tell when the transmitter shift register has
		* emptied so add a one-character drain delay.
		*/
		port->port.drain_delay = 1;

		return 0;