cdc-acm.c.patch

--- cdc-acm.c.orig	2013-06-12 09:45:17.796889900 -0500
+++ cdc-acm.c	2013-06-12 09:46:03.942769141 -0500
@@ -418,12 +418,21 @@
 	tty_flip_buffer_push(&acm->port);
 }
 
+#define P_MSG_TIME 0x5461
+static struct timespec p_msg_time;
+static uint8_t p_msg_time_valid = 0;
+
 static void acm_read_bulk_callback(struct urb *urb)
 {
 	struct acm_rb *rb = urb->context;
 	struct acm *acm = rb->instance;
 	unsigned long flags;
 
+        if(urb->actual_length == 1 && memcmp(urb->transfer_buffer, "P", 1) == 0) {
+          getnstimeofday(&p_msg_time);
+          p_msg_time_valid = 1;
+        }
+
 	dev_vdbg(&acm->data->dev, "%s - urb %d, len %d\n", __func__,
 					rb->index, urb->actual_length);
 	set_bit(rb->index, &acm->read_urbs_free);
@@ -834,6 +843,18 @@
 	case TIOCSSERIAL:
 		rv = set_serial_info(acm, (struct serial_struct __user *) arg);
 		break;
+        case P_MSG_TIME:
+                if(p_msg_time_valid) {
+                  if(copy_to_user((void __user *)arg, &p_msg_time, sizeof(p_msg_time))) {
+                    rv = -EFAULT;
+                  } else {
+                    rv = 0;
+                  }
+                  p_msg_time_valid = 0;
+                } else {
+                  rv = -ENOENT;
+                }
+                break;
 	}
 
 	return rv;