diff --git a/libsigrok4DSL/hardware/DSL/dsl.c b/libsigrok4DSL/hardware/DSL/dsl.c
index 8023b930..34c6cc38 100644
--- a/libsigrok4DSL/hardware/DSL/dsl.c
+++ b/libsigrok4DSL/hardware/DSL/dsl.c
@@ -348,8 +348,8 @@ static int hw_dev_open(struct sr_dev_driver *di, struct sr_dev_inst *sdi)
 
     ret = libusb_open(dev_handel, &usb->devhdl);
     if (ret != LIBUSB_SUCCESS){
-        sr_err("%s: Failed to open device: %s, handle:%p",
-                __func__, libusb_error_name(ret), dev_handel);
+        sr_err("%s:%d, Failed to open device: %s, handle:%p",
+                __func__, __LINE__, libusb_error_name(ret), dev_handel);
         ds_set_last_error(SR_ERR_DEVICE_IS_EXCLUSIVE);
         return SR_ERR;
     }
diff --git a/libsigrok4DSL/hardware/common/ezusb.c b/libsigrok4DSL/hardware/common/ezusb.c
index 7f67c8c7..3415a7ff 100644
--- a/libsigrok4DSL/hardware/common/ezusb.c
+++ b/libsigrok4DSL/hardware/common/ezusb.c
@@ -105,8 +105,8 @@ SR_PRIV int ezusb_upload_firmware(libusb_device *dev, int configuration,
 		libusb_get_bus_number(dev), libusb_get_device_address(dev));
 
 	if ((ret = libusb_open(dev, &hdl)) < 0) {
-        sr_err("%s: Failed to open device: %s.", 
-				__func__, libusb_error_name(ret));
+        sr_err("%s:%d, Failed to open device: %s.", 
+				__func__, __LINE__, libusb_error_name(ret));
         return SR_ERR;
 	}