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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: 7041d9c3f0 ("USB: serial: pl2303: add support for tx xon/xoff flow control")
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
This commit is contained in:
Johan Hovold 2019-04-02 10:19:30 +02:00
parent 79a3aaa7b8
commit 68270dab97
1 changed files with 20 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
drivers/usb/serial/pl2303.c
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@ -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);