From: Corey Minyard <cmimyard@xxxxxxxxxx> At least on the CP2105, sending this once doesn't work, you have to send it twice to make it happen. If you only send it once, you will get a really short time (a few bits) where the break is sent, right when the break is turned off, thus it isn't recognised as a break. Sending it twice won't hurt anything, so just do it all the time. Signed-off-by: Corey Minyard <cmimyard@xxxxxxxxxx> --- I played with this a bit, and found this change fixes the issue. It's not ideal, I suppose, but it works. drivers/usb/serial/cp210x.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c index cdea1bff3b70..e410a749325b 100644 --- a/drivers/usb/serial/cp210x.c +++ b/drivers/usb/serial/cp210x.c @@ -1446,6 +1446,15 @@ static void cp210x_break_ctl(struct tty_struct *tty, int break_state) dev_dbg(&port->dev, "%s - turning break %s\n", __func__, state == BREAK_OFF ? "off" : "on"); cp210x_write_u16_reg(port, CP210X_SET_BREAK, state); + /* + * At least on the CP2105, sending this once doesn't work, you + * have to send it twice to make it happen. If you only send + * it once, you will get a really short time (a few bits) where + * the break is sent, right when the break is turned off, thus + * it isn't recognised as a break. Sending it twice won't hurt + * anything, so just do it all the time. + */ + cp210x_write_u16_reg(port, CP210X_SET_BREAK, state); } #ifdef CONFIG_GPIOLIB -- 2.35.7
