From: Johan Hovold johan@kernel.org
commit ba4bbdabecd11530dca78dbae3ee7e51ffdc0a06 upstream.
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: 5951b8508855 ("USB: serial: cp210x: suppress modem-control errors") Cc: stable@vger.kernel.org # 5.11 Reviewed-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Johan Hovold johan@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/serial/cp210x.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)
--- a/drivers/usb/serial/cp210x.c +++ b/drivers/usb/serial/cp210x.c @@ -1136,6 +1136,7 @@ static void cp210x_set_flow_control(stru struct cp210x_flow_ctl flow_ctl; u32 flow_repl; u32 ctl_hs; + bool crtscts; int ret;
/* @@ -1195,14 +1196,14 @@ static void cp210x_set_flow_control(stru 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)) { @@ -1225,8 +1226,12 @@ static void cp210x_set_flow_control(stru 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); }