Commit ba4bbdab authored by Johan Hovold's avatar Johan Hovold
Browse files

USB: serial: cp210x: fix flow-control error handling 



Make sure that the driver crtscts state is not updated in the unlikely
event that the flow-control request fails. Not doing so could break RTS
control.

Fixes: 5951b850 ("USB: serial: cp210x: suppress modem-control errors")
Cc: stable@vger.kernel.org	# 5.11
Reviewed-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
parent 2d9a0070

drivers/usb/serial/cp210x.c

+8 −3
Original line number Diff line number Diff line
@@ -1190,6 +1190,7 @@ static void cp210x_set_flow_control(struct tty_struct *tty, 
	struct cp210x_flow_ctl flow_ctl;

	u32 flow_repl;

	u32 ctl_hs;

	bool crtscts;

	int ret;



	/*
@@ -1249,14 +1250,14 @@ static void cp210x_set_flow_control(struct tty_struct *tty, 
			flow_repl |= CP210X_SERIAL_RTS_FLOW_CTL;

		else

			flow_repl |= CP210X_SERIAL_RTS_INACTIVE;

		port_priv->crtscts = true;

		crtscts = true;

	} else {

		ctl_hs &= ~CP210X_SERIAL_CTS_HANDSHAKE;

		if (port_priv->rts)

			flow_repl |= CP210X_SERIAL_RTS_ACTIVE;

		else

			flow_repl |= CP210X_SERIAL_RTS_INACTIVE;

		port_priv->crtscts = false;

		crtscts = false;

	}



	if (I_IXOFF(tty)) {
@@ -1279,8 +1280,12 @@ static void cp210x_set_flow_control(struct tty_struct *tty, 
	flow_ctl.ulControlHandshake = cpu_to_le32(ctl_hs);

	flow_ctl.ulFlowReplace = cpu_to_le32(flow_repl);



	cp210x_write_reg_block(port, CP210X_SET_FLOW, &flow_ctl,

	ret = cp210x_write_reg_block(port, CP210X_SET_FLOW, &flow_ctl,

			sizeof(flow_ctl));

	if (ret)

		goto out_unlock;



	port_priv->crtscts = crtscts;

out_unlock:

	mutex_unlock(&port_priv->mutex);

}