Support hardware-level Xon/Xoff flow control in transmit direction with pl2303.
I only know how to get the hardware to do IXON/!IXANY with ^S/^Q as control characters, so I preserve the old behaviour for all other cases. Signed-off-by: Florian Zumbiehl <[email protected]> --- --- linux-4.16.9/drivers/usb/serial/pl2303.c.orig 2018-05-20 00:51:34.580966124 +0200 +++ linux-4.16.9/drivers/usb/serial/pl2303.c 2018-05-20 01:16:49.532730098 +0200 @@ -539,12 +539,18 @@ struct usb_serial *serial = port->serial; struct pl2303_serial_private *spriv = usb_get_serial_data(serial); struct pl2303_private *priv = usb_get_serial_port_data(port); + bool termios_unchanged; unsigned long flags; unsigned char *buf; int ret; u8 control; - if (old_termios && !tty_termios_hw_change(&tty->termios, old_termios)) + termios_unchanged = old_termios && + !(tty_termios_hw_change(&tty->termios, old_termios) || + ((tty->termios.c_iflag ^ old_termios->c_iflag) & (IXON | IXANY)) || + tty->termios.c_cc[VSTOP] != old_termios->c_cc[VSTOP] || + tty->termios.c_cc[VSTART] != old_termios->c_cc[VSTART]); + if (termios_unchanged) return; buf = kzalloc(7, GFP_KERNEL); @@ -662,6 +668,10 @@ pl2303_vendor_write(serial, 0x0, 0x41); else pl2303_vendor_write(serial, 0x0, 0x61); + } else if (I_IXON(tty) && !I_IXANY(tty) && + START_CHAR(tty) == 0x11 && + STOP_CHAR(tty) == 0x13) { + pl2303_vendor_write(serial, 0x0, 0xc0); } else { pl2303_vendor_write(serial, 0x0, 0x0); } -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
