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 <florz@xxxxxxxx>
---
--- 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);
}
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