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path: root/drivers/usb/serial/ch341.c
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Diffstat (limited to 'drivers/usb/serial/ch341.c')
-rw-r--r--drivers/usb/serial/ch341.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c
index 63f7cc45bca..7b8815ddf36 100644
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -486,12 +486,22 @@ static void ch341_read_int_callback(struct urb *urb)
if (actual_length >= 4) {
struct ch341_private *priv = usb_get_serial_port_data(port);
unsigned long flags;
+ u8 prev_line_status = priv->line_status;
spin_lock_irqsave(&priv->lock, flags);
priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT;
if ((data[1] & CH341_MULT_STAT))
priv->multi_status_change = 1;
spin_unlock_irqrestore(&priv->lock, flags);
+
+ if ((priv->line_status ^ prev_line_status) & CH341_BIT_DCD) {
+ struct tty_struct *tty = tty_port_tty_get(&port->port);
+ if (tty)
+ usb_serial_handle_dcd_change(port, tty,
+ priv->line_status & CH341_BIT_DCD);
+ tty_kref_put(tty);
+ }
+
wake_up_interruptible(&priv->delta_msr_wait);
}