From dbfd2866ac36bab52a4f37384e935eb5df76ad60 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Thu, 2 Jan 2014 22:49:22 +0100 Subject: [PATCH] USB: pl2303: only wake up MSR queue on changes Only wake up MSR wait queue on actual modem-status changes. Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman --- drivers/usb/serial/pl2303.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/drivers/usb/serial/pl2303.c b/drivers/usb/serial/pl2303.c index 11de1f16930..64f093f1698 100644 --- a/drivers/usb/serial/pl2303.c +++ b/drivers/usb/serial/pl2303.c @@ -118,6 +118,7 @@ MODULE_DEVICE_TABLE(usb, id_table); #define VENDOR_READ_REQUEST 0x01 #define UART_STATE_INDEX 8 +#define UART_STATE_MSR_MASK 0x8b #define UART_STATE_TRANSIENT_MASK 0x74 #define UART_DCD 0x01 #define UART_DSR 0x02 @@ -828,15 +829,17 @@ static void pl2303_update_line_status(struct usb_serial_port *port, if (status & UART_BREAK_ERROR) usb_serial_handle_break(port); - wake_up_interruptible(&port->port.delta_msr_wait); - - if (delta & UART_DCD) { - tty = tty_port_tty_get(&port->port); - if (tty) { - usb_serial_handle_dcd_change(port, tty, + if (delta & UART_STATE_MSR_MASK) { + if (delta & UART_DCD) { + tty = tty_port_tty_get(&port->port); + if (tty) { + usb_serial_handle_dcd_change(port, tty, status & UART_DCD); - tty_kref_put(tty); + tty_kref_put(tty); + } } + + wake_up_interruptible(&port->port.delta_msr_wait); } } -- 2.46.0