[aravis] gv_device: try harder to get the control register in heartbeat thread.

[Emmanuel Pacaud <emmanuel src gnome org>]

commit 3bcaf2ed9b7aa4bcde31311ec645fc7f5deabd1a
Author: Emmanuel Pacaud <emmanuel gnome org>
Date:   Wed Jul 6 22:21:17 2011 +0200

    gv_device: try harder to get the control register in heartbeat thread.
    
    Now control is delcared lost when we actually have the return value
    of the control register read command. This improves the reliability
    of the connection on crappy links, like wifi.

 docs/reference/aravis/aravis-sections.txt |    1 +
 src/arvgvdevice.c                         |   12 ++++++++++--
 src/arvgvdevice.h                         |    1 +
 3 files changed, 12 insertions(+), 2 deletions(-)
---
diff --git a/docs/reference/aravis/aravis-sections.txt b/docs/reference/aravis/aravis-sections.txt
index 4b5dbb6..cb56f92 100644
--- a/docs/reference/aravis/aravis-sections.txt
+++ b/docs/reference/aravis/aravis-sections.txt
@@ -430,6 +430,7 @@ ARV_GV_DEVICE_GET_CLASS
 ARV_GV_DEVICE_GVCP_N_RETRIES_DEFAULT
 ARV_GV_DEVICE_GVCP_TIMEOUT_MS_DEFAULT
 ARV_GV_DEVICE_GVSP_PACKET_SIZE_DEFAULT
+ARV_GV_DEVICE_HEARTBEAT_RETRY_DELAY_US
 ARV_GV_DEVICE_BUFFER_SIZE
 ArvGvDeviceClass
 ArvGvDevicePrivate
diff --git a/src/arvgvdevice.c b/src/arvgvdevice.c
index e74325f..2942749 100644
--- a/src/arvgvdevice.c
+++ b/src/arvgvdevice.c
@@ -348,13 +348,21 @@ arv_gv_device_heartbeat_thread (void *data)
 		g_usleep (thread_data->period_us);
 
 		if (io_data->is_controller) {
+			guint counter = 1;
 
 			/* TODO: Instead of reading the control register, Pylon does write the heartbeat
 			 * timeout value, which is interresting, as doing this we could get an error
 			 * ack packet which will indicate we lost the control access. */
 
-			_read_register (io_data, ARV_GVBS_CONTROL_CHANNEL_PRIVILEGE_OFFSET, &value);
-			arv_log_device ("[GvDevice::Heartbeat] (%d)", value);
+			while (!_read_register (io_data, ARV_GVBS_CONTROL_CHANNEL_PRIVILEGE_OFFSET, &value)) {
+				g_usleep (ARV_GV_DEVICE_HEARTBEAT_RETRY_DELAY_US);
+				counter++;
+			}
+
+			arv_log_device ("[GvDevice::Heartbeat] Ack value = %d", value);
+
+			if (counter > 1)
+				arv_log_device ("[GvDevice::Heartbeat] Tried %u times", counter);
 
 			if ((value & (ARV_GVBS_CONTROL_CHANNEL_PRIVILEGE_CONTROL |
 				      ARV_GVBS_CONTROL_CHANNEL_PRIVILEGE_EXCLUSIVE)) == 0) {
diff --git a/src/arvgvdevice.h b/src/arvgvdevice.h
index 190af79..36a9978 100644
--- a/src/arvgvdevice.h
+++ b/src/arvgvdevice.h
@@ -31,6 +31,7 @@ G_BEGIN_DECLS
 
 #define	ARV_GV_DEVICE_GVCP_N_RETRIES_DEFAULT	5
 #define	ARV_GV_DEVICE_GVCP_TIMEOUT_MS_DEFAULT	500
+#define	ARV_GV_DEVICE_HEARTBEAT_RETRY_DELAY_US	10000
 
 #define ARV_GV_DEVICE_GVSP_PACKET_SIZE_DEFAULT	1500