Support hardware-level Xon/Xoff flow control in transmit direction with pl2303.
Signed-off-by: Florian Zumbiehl <[email protected]> --- Note that the patch has only been fully tested with kernel 4.9.28, and test-compiled against 4.16.8. Tested only with the pl2303 adapters I have available (which seem to be type 0 if I interpret the code correctly), I don't have a clue whether this works with other versions of the chip. --- linux-4.16.8/drivers/usb/serial/pl2303.c.orig 2018-05-09 09:53:14.000000000 +0200 +++ linux-4.16.8/drivers/usb/serial/pl2303.c 2018-05-14 04:32:27.860780856 +0200 @@ -544,8 +544,12 @@ static void pl2303_set_termios(struct tt int ret; u8 control; - if (old_termios && !tty_termios_hw_change(&tty->termios, old_termios)) - return; + if (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])) + return; buf = kzalloc(7, GFP_KERNEL); if (!buf) { @@ -662,6 +666,9 @@ static void pl2303_set_termios(struct tt 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
