Make restarting of GPUs optional for systems that hang on any attempt to restart them.

Fix DEAD status by comparing it to last live time rather than last attempted restart time since that happens every minute.

main.c

@@ -192,6 +192,7 @@ int opt_worksize;
 int opt_scantime = 60;
 int opt_bench_algo = -1;
 static const bool opt_time = true;
+static bool opt_restart = true;
 #if defined(WANT_X8664_SSE4) && defined(__SSE4_1__)
 static enum sha256_algos opt_algo = ALGO_SSE4_64;
 #elif defined(WANT_X8664_SSE2) && defined(__SSE2__)
@@ -1078,6 +1079,11 @@ static struct opt_table opt_config_table[] = {
 	OPT_WITHOUT_ARG("--no-longpoll",
 			opt_set_invbool, &want_longpoll,
 			"Disable X-Long-Polling support"),
+#ifdef HAVE_OPENCL
+	OPT_WITHOUT_ARG("--no-restart",
+			opt_set_invbool, &opt_restart,
+			"Do not attempt to restart GPUs that hang"),
+#endif
 	OPT_WITH_ARG("--pass|-p",
 		     set_pass, NULL, &trpc_pass,
 		     "Password for bitcoin JSON-RPC server"),
@@ -4199,15 +4205,18 @@ static void *watchdog_thread(void *userdata)
 				thr->rolling = thr->cgpu->rolling = 0;
 				gpus[gpu].status = LIFE_SICK;
 				applog(LOG_ERR, "Thread %d idle for more than 60 seconds, GPU %d declared SICK!", i, gpu);
-				applog(LOG_ERR, "Attempting to restart GPU");
 				gettimeofday(&thr->sick, NULL);
+				if (opt_restart) {
+					applog(LOG_ERR, "Attempting to restart GPU");
 					reinit_device(thr->cgpu);
-			} else if (now.tv_sec - thr->sick.tv_sec > 600 && gpus[i].status == LIFE_SICK) {
+				}
+			} else if (now.tv_sec - thr->last.tv_sec > 600 && gpus[i].status == LIFE_SICK) {
 				gpus[gpu].status = LIFE_DEAD;
 				applog(LOG_ERR, "Thread %d not responding for more than 10 minutes, GPU %d declared DEAD!", i, gpu);
 			} else if (now.tv_sec - thr->sick.tv_sec > 60 && gpus[i].status == LIFE_SICK) {
 				/* Attempt to restart a GPU once every minute */
 				gettimeofday(&thr->sick, NULL);
+				if (opt_restart)
 					reinit_device(thr->cgpu);
 			}
 		}