Commit 68270dab authored by Johan Hovold's avatar Johan Hovold
Browse files

USB: serial: pl2303: fix non-supported xon/xoff 



Older pl2303 devices do not support automatic xon/xoff flow control, so
add add a flag to prevent trying to enable it for legacy device types.

Refactor the IXON test into a helper function to improve readability.

Fixes: 7041d9c3 ("USB: serial: pl2303: add support for tx xon/xoff flow control")
Reviewed-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
parent 79a3aaa7

drivers/usb/serial/pl2303.c

+20 −5
Original line number Diff line number Diff line
@@ -156,6 +156,7 @@ enum pl2303_type { 
struct pl2303_type_data {

	speed_t max_baud_rate;

	unsigned long quirks;

	unsigned int no_autoxonxoff:1;

};



struct pl2303_serial_private {
@@ -175,6 +176,7 @@ static const struct pl2303_type_data pl2303_type_data[TYPE_COUNT] = { 
	[TYPE_01] = {

		.max_baud_rate		= 1228800,

		.quirks			= PL2303_QUIRK_LEGACY,

		.no_autoxonxoff		= true,

	},

	[TYPE_HX] = {

		.max_baud_rate		= 12000000,
@@ -552,6 +554,20 @@ static bool pl2303_termios_change(const struct ktermios *a, const struct ktermio 
	return tty_termios_hw_change(a, b) || ixon_change;

}



static bool pl2303_enable_xonxoff(struct tty_struct *tty, const struct pl2303_type_data *type)

{

	if (!I_IXON(tty) || I_IXANY(tty))

		return false;



	if (START_CHAR(tty) != 0x11 || STOP_CHAR(tty) != 0x13)

		return false;



	if (type->no_autoxonxoff)

		return false;



	return true;

}



static void pl2303_set_termios(struct tty_struct *tty,

		struct usb_serial_port *port, struct ktermios *old_termios)

{
@@ -681,8 +697,7 @@ static void pl2303_set_termios(struct tty_struct *tty, 
			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) {

	} else if (pl2303_enable_xonxoff(tty, spriv->type)) {

		pl2303_vendor_write(serial, 0x0, 0xc0);

	} else {

		pl2303_vendor_write(serial, 0x0, 0x0);

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