At Mon, 29 Nov 2010 17:40:03 +0900, Amit Nagal wrote:
Hi ,
Thanx for the reply .
we tried SNDCTL_DSP_RESET , but it is not flushing the kernel pcm buffer for us .
It should. It abandons the pending data and resets to the initial state before starting the stream.
But, it might be a bug in OSS emulation later. It doesn't seem to reset the internal buffer. Try the patch below.
any other method which we can use ?
also please lets us the function available with alsa - lib which serves the purpose of flushing the kernel pcm buffer .
snd_pcm_drop() corresponds to it.
Takashi
--- diff --git a/sound/core/oss/pcm_oss.c b/sound/core/oss/pcm_oss.c index 5c8c7df..a4411a3 100644 --- a/sound/core/oss/pcm_oss.c +++ b/sound/core/oss/pcm_oss.c @@ -1510,16 +1510,19 @@ static ssize_t snd_pcm_oss_read1(struct snd_pcm_substream *substream, char __use static int snd_pcm_oss_reset(struct snd_pcm_oss_file *pcm_oss_file) { struct snd_pcm_substream *substream; + struct snd_pcm_runtime *runtime; + int i;
- substream = pcm_oss_file->streams[SNDRV_PCM_STREAM_PLAYBACK]; - if (substream != NULL) { - snd_pcm_kernel_ioctl(substream, SNDRV_PCM_IOCTL_DROP, NULL); - substream->runtime->oss.prepare = 1; - } - substream = pcm_oss_file->streams[SNDRV_PCM_STREAM_CAPTURE]; - if (substream != NULL) { + for (i = 0; i < 2; i++) { + substream = pcm_oss_file->streams[i]; + if (!substream) + continue; + runtime = substream->runtine; snd_pcm_kernel_ioctl(substream, SNDRV_PCM_IOCTL_DROP, NULL); - substream->runtime->oss.prepare = 1; + runtime->oss.prepare = 1; + runtime->oss.buffer_used = 0; + runtime->oss.prev_hw_ptr_period = 0; + runtime->oss.period_ptr = 0; } return 0; }