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: 7041d9c3f01b ("USB: serial: pl2303: add support for tx xon/xoff flow control")
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
---
drivers/usb/serial/pl2303.c | 25 ++++++++++++++++++++-----
1 file changed, 20 insertions(+), 5 deletions(-)
diff --git a/drivers/usb/serial/pl2303.c b/drivers/usb/serial/pl2303.c
index bb3f9aa4a909..e7ccd06df802 100644
--- a/drivers/usb/serial/pl2303.c
+++ b/drivers/usb/serial/pl2303.c
@@ -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 {
@@ -173,11 +174,12 @@ struct pl2303_private {
static const struct pl2303_type_data pl2303_type_data[TYPE_COUNT] = {
[TYPE_01] = {
- .max_baud_rate = 1228800,
- .quirks = PL2303_QUIRK_LEGACY,
+ .max_baud_rate = 1228800,
+ .quirks = PL2303_QUIRK_LEGACY,
+ .no_autoxonxoff = 1,
},
[TYPE_HX] = {
- .max_baud_rate = 12000000,
+ .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);
--
2.21.0
