genesys: Limit maximum bulk transfer size to allow data capture

backend/genesys_low.h

@@ -203,8 +203,14 @@
 #define BULK_RAM		0x00
 #define BULK_REGISTER		0x11
 
-#define BULKIN_MAXSIZE          0xFE00
-#define GL646_BULKIN_MAXSIZE    0xFFC0
+/*  Genesys supports 0xFE00 maximum size in general, wheraus GL646 supports
+    0xFFC0. We use 0xF000 because that's the packet limit in the Linux usbmon
+    USB capture stack. By default it limits packet size to b_size / 5 where
+    b_size is the size of the ring buffer. By default it's 300*1024, so the
+    packet is limited 61440 without any visibility to acquiring software.
+*/
+#define BULKIN_MAXSIZE          0xF000
+#define GL646_BULKIN_MAXSIZE    0xF000
 #define GL646_BULKIN_MINSIZE    0x0800
 #define BULKOUT_MAXSIZE         0xF000