diff --git a/main/channel.c b/main/channel.c
index 58861add9c..07bc5d474f 100644
--- a/main/channel.c
+++ b/main/channel.c
@@ -2105,12 +2105,14 @@ static struct ast_frame *__ast_read(struct ast_channel *chan, int dropaudio)
 				/* save a copy of func/data before unlocking the channel */
 				int (*func)(const void *) = chan->timingfunc;
 				void *data = chan->timingdata;
+				chan->fdno = -1;
 				ast_channel_unlock(chan);
 				func(data);
 			} else {
 				blah = 0;
 				ioctl(chan->timingfd, DAHDI_TIMERCONFIG, &blah);
 				chan->timingdata = NULL;
+				chan->fdno = -1;
 				ast_channel_unlock(chan);
 			}
 			/* cannot 'goto done' because the channel is already unlocked */
@@ -2128,6 +2130,7 @@ static struct ast_frame *__ast_read(struct ast_channel *chan, int dropaudio)
 		chan->generator->generate(chan, tmp, -1, -1);
 		chan->generatordata = tmp;
 		f = &ast_null_frame;
+		chan->fdno = -1;
 		goto done;
 	}
 
@@ -2185,7 +2188,7 @@ static struct ast_frame *__ast_read(struct ast_channel *chan, int dropaudio)
 			ast_log(LOG_WARNING, "No read routine on channel %s\n", chan->name);
 	}
 
-        /*
+	/*
 	 * Reset the recorded file descriptor that triggered this read so that we can
 	 * easily detect when ast_read() is called without properly using ast_waitfor().
 	 */