+ if (!ssi_private->first_stream)
+ ssi_private->first_stream = substream;
+ else {
+ /* This is the second stream open, so we need to impose sample
+ * rate and maybe sample size constraints. Note that this can
+ * cause a race condition if the second stream is opened before
+ * the first stream is fully initialized.
+ *
+ * We provide some protection by checking to make sure the first
+ * stream is initialized, but it's not perfect. ALSA sometimes
+ * re-initializes the driver with a different sample rate or
+ * size. If the second stream is opened before the first stream
+ * has received its final parameters, then the second stream may
+ * be constrained to the wrong sample rate or size.
+ *
+ * FIXME: This code does not handle opening and closing streams
+ * repeatedly. If you open two streams and then close the first
+ * one, you may not be able to open another stream until you
+ * close the second one as well.
+ */
+ struct snd_pcm_runtime *first_runtime =
+ ssi_private->first_stream->runtime;
+
+ if (!first_runtime->rate || !first_runtime->sample_bits) {
+ dev_err(substream->pcm->card->dev,
+ "set sample rate and size in %s stream first\n",
+ substream->stream == SNDRV_PCM_STREAM_PLAYBACK
+ ? "capture" : "playback");
+ return -EAGAIN;
+ }
+
+ snd_pcm_hw_constraint_minmax(substream->runtime,
+ SNDRV_PCM_HW_PARAM_RATE,
+ first_runtime->rate, first_runtime->rate);
+
+ snd_pcm_hw_constraint_minmax(substream->runtime,
+ SNDRV_PCM_HW_PARAM_SAMPLE_BITS,
+ first_runtime->sample_bits,
+ first_runtime->sample_bits);
+
+ ssi_private->second_stream = substream;
+ }
+