hackrf_info: Report whether other devices are sharing the USB bus.

host/hackrf-tools/src/hackrf_info.c

@@ -22,6 +22,7 @@
  */
 
 #include <hackrf.h>
+#include <libusb-1.0/libusb.h>
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -95,6 +96,8 @@ int main(void)
 	hackrf_device_list_t* list;
 	hackrf_device* device;
 	int i, j;
+	libusb_device *usb_dev, *hackrf_dev;
+	uint8_t hackrf_bus, other_device_count;
 
 	result = hackrf_init();
 	if (result != HACKRF_SUCCESS) {
@@ -254,6 +257,31 @@ int main(void)
 				hackrf_error_name(result),
 				result);
 		}
+
+		// Count devices that are sharing the USB bus with this HackRF.
+		hackrf_dev = list->usb_devices[list->usb_device_index[i]];
+		hackrf_bus = libusb_get_bus_number(hackrf_dev);
+		other_device_count = 0;
+		for (j = 0; j < list->usb_devicecount; j++) {
+			usb_dev = (libusb_device*) list->usb_devices[j];
+			// Don't count the HackRF, devices on other buses, or the root hub.
+			if (usb_dev != hackrf_dev &&
+			    libusb_get_bus_number(usb_dev) == hackrf_bus &&
+			    libusb_get_parent(usb_dev) != NULL) {
+				other_device_count++;
+			}
+		}
+		if (other_device_count == 0) {
+			printf("This device is on its own USB bus.\n");
+		} else {
+			if (other_device_count == 1) {
+				printf("There is 1 other device on the same USB bus.\n");
+			} else {
+				printf("There are %d other devices on the same USB bus.\n",
+				       other_device_count);
+			}
+			printf("You may have problems at high sample rates.\n");
+		}
 	}
 
 	hackrf_device_list_free(list);