Attempt to initialise while bitforce device returns BUSY.

driver-bitforce.c

@@ -176,6 +176,7 @@ void bitforce_init(struct cgpu_info *bitforce)
 		return;
 	}
 
+	do {
 		BFwrite(fdDev, "ZGX", 3);
 		BFgets(pdevbuf, sizeof(pdevbuf), fdDev);
 
@@ -184,6 +185,7 @@ void bitforce_init(struct cgpu_info *bitforce)
 			applog(LOG_ERR, "BFL%i: Error reading (ZGX)", bitforce->device_id);
 			return;
 		}
+	} while (!strstr(pdevbuf, "BUSY"));
 
 	if (unlikely(!strstr(pdevbuf, "SHA256"))) {
 		mutex_unlock(&bitforce->device_mutex);