Index: channels/chan_dahdi.c
===================================================================
--- channels/chan_dahdi.c	(revision 189119)
+++ channels/chan_dahdi.c	(working copy)
@@ -6510,7 +6510,7 @@
 			ast_setstate(chan, AST_STATE_RING);
 			while (time(NULL) < start + 3) {
 				res = ast_waitfor(chan, 1000);
-				if (res) {
+				if (res > 0) {
 					f = ast_read(chan);
 					if (!f) {
 						ast_log(LOG_WARNING, "Whoa, hangup while waiting for first ring!\n");
Index: main/channel.c
===================================================================
--- main/channel.c	(revision 189119)
+++ main/channel.c	(working copy)
@@ -1823,9 +1823,10 @@
 {
 	int oldms = ms;	/* -1 if no timeout */
 
-	ast_waitfor_nandfds(&c, 1, NULL, 0, NULL, NULL, &ms);
-	if ((ms < 0) && (oldms < 0))
-		ms = 0;
+	c = ast_waitfor_nandfds(&c, 1, NULL, 0, NULL, NULL, &ms);
+	if (c && oldms < 0) {
+		ms = 1;
+	}
 	return ms;
 }
 
@@ -2039,12 +2040,6 @@
 		usleep(1);
 	}
 
-	if (chan->fdno == -1) {
-		ast_log(LOG_ERROR, "ast_read() called with no recorded file descriptor.\n");
-		f = &ast_null_frame;
-		goto done;
-	}
-
 	if (chan->masq) {
 		if (ast_do_masquerade(chan))
 			ast_log(LOG_WARNING, "Failed to perform masquerade\n");
@@ -2059,6 +2054,12 @@
 			ast_deactivate_generator(chan);
 		goto done;
 	}
+
+	if (chan->fdno == -1) {
+		ast_log(LOG_ERROR, "ast_read() called with no recorded file descriptor.\n");
+		f = &ast_null_frame;
+		goto done;
+	}
 	prestate = chan->_state;
 
 	/* Read and ignore anything on the alertpipe, but read only
@@ -4502,12 +4503,16 @@
 		return res;
 
 	/* Give us some wiggle room */
-	while (chan->generatordata && ast_waitfor(chan, 100) >= 0) {
-		struct ast_frame *f = ast_read(chan);
-		if (f)
+	while (chan->generatordata && (res = ast_waitfor(chan, 100)) >= 0) {
+		struct ast_frame *f;
+		if (!res) {
+			continue;
+		}
+		if ((f = ast_read(chan))) {
 			ast_frfree(f);
-		else
+		} else {
 			return -1;
+		}
 	}
 	return 0;
 }
Index: res/res_agi.c
===================================================================
--- res/res_agi.c	(revision 189119)
+++ res/res_agi.c	(working copy)
@@ -1004,6 +1004,9 @@
 					ast_dsp_free(sildet);
 				return RESULT_FAILURE;
 			}
+			if (res == 0) {
+				continue;
+			}
 			f = ast_read(chan);
 			if (!f) {
 				fdprintf(agi->fd, "200 result=%d (hangup) endpos=%ld\n", -1, sample_offset);