Ok, I got it.
I use marvell pxa2128 chip include ZSP core that connection codec, my aim to let zsp complete independence alsa work. When ALSA send AUDIO_STREAM_CMDID_TRIGGER command to ZSP, ZSP firmware do config something and then send AUDIO_STREAM_CMDID_DATARXTXREQ command to ALSA, then the ALSA send write/read pointer to ZSP, the ZSP through write/read pointer to fetch/transfer data, after process the ZSP send AUDIO_STREAM_CMDID_DATARXTX command to ALSA, then the ALSA change write/read pointer. My driver code below:
static snd_pcm_uframes_t mmp_zsp_pcm_pointer(struct snd_pcm_substream *substream) { struct snd_pcm_runtime *runtime = substream->runtime; struct pxa910_runtime_data *prtd = runtime->private_data; snd_pcm_uframes_t x;
x = prtd->zsp_buf.zsp_offset; x = bytes_to_frames(runtime, x); if (x == prtd->zsp_buf.buf_len/4) x = 0;
return x; }
static void zsp_msg_handler(struct work_struct *work) { ...... ..... case AUDIO_STREAM_CMDID_DATARXTXREQ: p_zsp_req = (cmd_audio_stream_datarxtxreq_t *)\ &zsp_data_received; len1 = get_zsp_buf_avail(&prtd->zsp_buf); len2 = get_fw_avail(p_zsp_req, substream->stream); len3 = get_buf_avail(&prtd->zsp_buf, substream->stream); tsize = ((len1 < len2) ? len1 : len2); if ((tsize == len1) && (len1 == len3) && (tsize >= \ 2 * prtd->zsp_buf.zsp_period_bytes)) { tsize -= prtd->zsp_buf.zsp_period_bytes; } cmd_strm_tx.command_id = AUDIO_STREAM_CMDID_DATARXTX; cmd_strm_tx.stream_id = prtd->stream_id; cmd_strm_tx.addr = prtd->zsp_buf.buf_phys + \ prtd->zsp_buf.zsp_offset; cmd_strm_tx.size = tsize; kzmq_write(prtd->zmq_deliver, (void *)&cmd_strm_tx, sizeof(cmd_audio_stream_datarxtx_t)); if ((prtd->zsp_buf.zsp_offset + tsize) >= \ (prtd->zsp_buf.buf_len)) prtd->zsp_buf.zsp_offset = 0; else prtd->zsp_buf.zsp_offset += \ tsize; break; case AUDIO_STREAM_CMDID_DATARXTX: snd_pcm_period_elapsed(substream); break;
}
When I use arecord command occue "overrun", I don't know I explain problem clear or not. Thanks a lot. -- Best Regards, Zhen Fu
-----Original Message----- From: alsa-devel-bounces@alsa-project.org [mailto:alsa-devel-bounces@alsa-project.org] On Behalf Of Clemens Ladisch Sent: Friday, July 06, 2012 3:17 PM To: alsa-devel@alsa-project.org Subject: Re: [alsa-devel] then there was "overrun" occue every time once trigger the audio recording
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Zhen Fu wrote:
When I use arecord command, then there was "overrun" occue every time once trigger the audio recording. I have no clue of alsa driver when and how handler xrun. In other words, how to understand function snd_pcm_update_hw_ptr0 in pcm_lib.c.
It behaves pretty much the same for playback and capture, so I refer the honourable gentleman to the reply I gave some moments ago.
If you want a more specific answer, it might be a good idea not to keep the hardware and your driver source code a secret.
Regards, Clemens _______________________________________________ Alsa-devel mailing list Alsa-devel@alsa-project.org http://mailman.alsa-project.org/mailman/listinfo/alsa-devel