Fix to prevent loss of first 2 frames during capture (due to the init…

…ial FPGA buffer flush)
simoninns · Dec 26, 2017 · 358ac37 · 358ac37
1 parent 3916f85
commit 358ac37
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Showing 3 changed files with 17 additions and 0 deletions.
diff --git a/Linux-Application/DomesdayDuplicator/QtUsb/qlibusb.cpp b/Linux-Application/DomesdayDuplicator/QtUsb/qlibusb.cpp
@@ -354,6 +354,9 @@ qint32 QUsbDevice::startBulkTransfer(bool testMode, QString fileName)
     mUsbBulkTransfer->setup(mCtx, mDevHandle, mConfig.readEp, testMode, fileName);
     mUsbBulkTransfer->start();
 
+    // Wait for the transfer to start
+    while(!mUsbBulkTransfer->isTransferRunning());
+
     return rc;
 }
 

diff --git a/Linux-Application/DomesdayDuplicator/QtUsb/qusbbulktransfer.cpp b/Linux-Application/DomesdayDuplicator/QtUsb/qusbbulktransfer.cpp
@@ -69,6 +69,9 @@ struct statisticsStruct {
 };
 static statisticsStruct statistics;
 
+// Flag to show if transfer is in progress
+bool transferRunning;
+
 // Notes:
 //
 // The ADC generates data at a rate of around 64Mbytes/sec
@@ -126,6 +129,7 @@ QUsbBulkTransfer::QUsbBulkTransfer(void)
 {
     stopUsbTransfers = false;
     stopDiskTransfers = false;
+    transferRunning = false;
     qDebug() << "QUsbBulkTransfer::QUsbBulkTransfer(): Called";
 }
 
@@ -164,6 +168,11 @@ void QUsbBulkTransfer::setup(libusb_context* mCtx, libusb_device_handle* devHand
     captureFileName = fileName;
 }
 
+// Return true if transfer is running
+bool QUsbBulkTransfer::isTransferRunning(void) {
+    return transferRunning;
+}
+
 void QUsbBulkTransfer::run()
 {
     // These variables are referenced by the callback and must remain valid
@@ -191,6 +200,7 @@ void QUsbBulkTransfer::run()
     gettimeofday(&statistics.startTimestamp, NULL);
 
     // Reset transfer variables
+    transferRunning = false;
     transfersInFlight = 0;      // Number of transfers that are in progress (global)
     requestSize = REQUEST_SIZE; // Request size (number of packets)
     packetSize = PACKET_SIZE;   // Maximum packet size for the endpoint (in bytes)
@@ -588,6 +598,9 @@ static void LIBUSB_CALL bulkTransferCallback(struct libusb_transfer *transfer)
         statistics.startTimestamp = endTimestamp;
     }
 
+    // If the buffer flush is complete, flag the transfer as running
+    if (bufferFlushComplete) transferRunning = true;
+
     // Write received data to disk (unless we are performing a buffer flush)
     if (bufferFlushComplete) {
         // Disk buffer handling

diff --git a/Linux-Application/DomesdayDuplicator/QtUsb/qusbbulktransfer.h b/Linux-Application/DomesdayDuplicator/QtUsb/qusbbulktransfer.h
@@ -50,6 +50,7 @@ class QUsbBulkTransfer : public QThread {
     quint32 getTestFailureCounter(void);
     quint32 getAvailableDiskBuffers(void);
     quint32 getNumberOfDiskBuffers(void);
+    bool isTransferRunning(void);
 
 signals: