Only wake up MSR wait queue on actual modem-status changes.
Signed-off-by: Johan Hovold <[email protected]>
---
drivers/usb/serial/cypress_m8.c | 5 ++++-
drivers/usb/serial/cypress_m8.h | 1 +
2 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/serial/cypress_m8.c b/drivers/usb/serial/cypress_m8.c
index 558605d646f3..07e003398613 100644
--- a/drivers/usb/serial/cypress_m8.c
+++ b/drivers/usb/serial/cypress_m8.c
@@ -1187,7 +1187,10 @@ static void cypress_read_int_callback(struct urb *urb)
if (priv->current_status != priv->prev_status) {
priv->diff_status |= priv->current_status ^
priv->prev_status;
- wake_up_interruptible(&port->port.delta_msr_wait);
+
+ if (priv->diff_status & UART_MSR_MASK)
+ wake_up_interruptible(&port->port.delta_msr_wait);
+
priv->prev_status = priv->current_status;
}
spin_unlock_irqrestore(&priv->lock, flags);
diff --git a/drivers/usb/serial/cypress_m8.h b/drivers/usb/serial/cypress_m8.h
index 68bfd5197a63..119d2e17077b 100644
--- a/drivers/usb/serial/cypress_m8.h
+++ b/drivers/usb/serial/cypress_m8.h
@@ -66,6 +66,7 @@
#define CONTROL_RTS 0x10 /* request to send */
#define CONTROL_RESET 0x08 /* sent with output report */
+#define UART_MSR_MASK 0xf0
#define UART_RI 0x80 /* ring indicator */
#define UART_CD 0x40 /* carrier detect */
#define UART_DSR 0x20 /* data set ready */
--
1.8.3.2
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