diff --git a/lib/libusb/Makefile b/lib/libusb/Makefile
index 7a9bd1b23678..d45dd567b437 100644
--- a/lib/libusb/Makefile
+++ b/lib/libusb/Makefile
@@ -18,6 +18,9 @@ NOGCCERROR=
 
 WARNS?=		2
 
+DPADD=		${LIBPTHREAD}
+LDADD=		-lpthread
+
 MLINKS+=	libusb.3 usb.3
 
 # libusb 0.1 compat
diff --git a/lib/libusb/libusb10.c b/lib/libusb/libusb10.c
index 44331bc6ad3c..256d67e93bc5 100644
--- a/lib/libusb/libusb10.c
+++ b/lib/libusb/libusb10.c
@@ -92,6 +92,7 @@ int
 libusb_init(libusb_context **context)
 {
 	struct libusb_context *ctx;
+	pthread_condattr_t attr;
 	char *debug;
 	int ret;
 
@@ -110,8 +111,28 @@ libusb_init(libusb_context **context)
 	TAILQ_INIT(&ctx->pollfds);
 	TAILQ_INIT(&ctx->tr_done);
 
-	pthread_mutex_init(&ctx->ctx_lock, NULL);
-	pthread_cond_init(&ctx->ctx_cond, NULL);
+	if (pthread_mutex_init(&ctx->ctx_lock, NULL) != 0) {
+		free(ctx);
+		return (LIBUSB_ERROR_NO_MEM);
+	}
+	if (pthread_condattr_init(&attr) != 0) {
+		pthread_mutex_destroy(&ctx->ctx_lock);
+		free(ctx);
+		return (LIBUSB_ERROR_NO_MEM);
+	}
+	if (pthread_condattr_setclock(&attr, CLOCK_MONOTONIC) != 0) {
+		pthread_mutex_destroy(&ctx->ctx_lock);
+		pthread_condattr_destroy(&attr);
+		free(ctx);
+		return (LIBUSB_ERROR_OTHER);
+	}
+	if (pthread_cond_init(&ctx->ctx_cond, &attr) != 0) {
+		pthread_mutex_destroy(&ctx->ctx_lock);
+		pthread_condattr_destroy(&attr);
+		free(ctx);
+		return (LIBUSB_ERROR_NO_MEM);
+	}
+	pthread_condattr_destroy(&attr);
 
 	ctx->ctx_handler = NO_THREAD;
 
diff --git a/lib/libusb/libusb10_io.c b/lib/libusb/libusb10_io.c
index 63f833af8828..302fdb8dda32 100644
--- a/lib/libusb/libusb10_io.c
+++ b/lib/libusb/libusb10_io.c
@@ -307,12 +307,16 @@ libusb_wait_for_event(libusb_context *ctx, struct timeval *tv)
 		    &ctx->ctx_lock);
 		return (0);
 	}
-	err = clock_gettime(CLOCK_REALTIME, &ts);
+	err = clock_gettime(CLOCK_MONOTONIC, &ts);
 	if (err < 0)
 		return (LIBUSB_ERROR_OTHER);
 
-	ts.tv_sec = tv->tv_sec;
-	ts.tv_nsec = tv->tv_usec * 1000;
+	/*
+	 * The "tv" arguments points to a relative time structure and
+	 * not an absolute time structure.
+	 */
+	ts.tv_sec += tv->tv_sec;
+	ts.tv_nsec += tv->tv_usec * 1000;
 	if (ts.tv_nsec >= 1000000000) {
 		ts.tv_nsec -= 1000000000;
 		ts.tv_sec++;