[PATCH] fix infinite draining of the rate plugin in SND_PCM_NONBLOCK mode

[sylvain.bertrand@gmail.com]

The draining function of the rate plugin does not handle properly the
SND_PCM_NONBLOCK case. It can write data to the slave plugin each time the
function is called, but does not update its internal state in order to
reach a stopping condition. Use a last_commit_ptr workaround to reach such
condition.

signed-off-by: Sylvain BERTRAND <sylvain.bertrand@legeek.net>
---
 src/pcm/pcm_rate.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)
---
diff --git a/src/pcm/pcm_rate.c b/src/pcm/pcm_rate.c
index 21611f62..25574a50 100644
--- a/src/pcm/pcm_rate.c
+++ b/src/pcm/pcm_rate.c
@@ -1051,6 +1051,7 @@ static int snd_pcm_rate_drain(snd_pcm_t *pcm)
 		/* commit the remaining fraction (if any) */
 		snd_pcm_uframes_t size, ofs, saved_avail_min;
 		snd_pcm_sw_params_t sw_params;
+		int commit_err;
 
 		__snd_pcm_lock(pcm);
 		/* temporarily set avail_min to one */
@@ -1066,7 +1067,7 @@ static int snd_pcm_rate_drain(snd_pcm_t *pcm)
 		while (size > 0) {
 			snd_pcm_uframes_t psize, spsize;
 			int err;
-
+			
 			err = __snd_pcm_wait_in_lock(rate->gen.slave, -1);
 			if (err < 0)
 				break;
@@ -1079,14 +1080,29 @@ static int snd_pcm_rate_drain(snd_pcm_t *pcm)
 				if (! spsize)
 					break;
 			}
-			snd_pcm_rate_commit_area(pcm, rate, ofs,
+			commit_err = snd_pcm_rate_commit_area(pcm, rate, ofs,
 						 psize, spsize);
+			if (commit_err == 1) {
+				rate->last_commit_ptr += psize;
+				if (rate->last_commit_ptr >= pcm->boundary)
+					rate->last_commit_ptr = 0;
+			} else if (commit_err == 0) {
+				if (pcm->mode & SND_PCM_NONBLOCK != 0) {
+					commit_err = -EAGAIN;
+					break;
+				}
+				continue;
+			} else
+				break;
+
 			ofs = (ofs + psize) % pcm->buffer_size;
 			size -= psize;
 		}
 		sw_params.avail_min = saved_avail_min;
 		snd_pcm_sw_params(rate->gen.slave, &sw_params);
 		__snd_pcm_unlock(pcm);
+		if (commit_err < 0)
+			return commit_err;
 	}
 	return snd_pcm_drain(rate->gen.slave);
 }