Hi,
I already pulled it, but below are some comments.
At Mon, 29 Sep 2008 14:44:31 +0100,
Mark Brown wrote:
>
> From: Cliff Cai <cliff.cai@xxxxxxxxxx>
>
> With MMAP enabled (DMA mode) on the AD1981, there is +/- 250ms of delay between
> writing data to alsa and audio starts coming out of the AD1981.
>
> Copy more data to local buffer before starting DMA
>
> Signed-off-by: Cliff Cai <cliff.cai@xxxxxxxxxx>
> Signed-off-by: Bryan Wu <cooloney@xxxxxxxxxx>
> Signed-off-by: Mark Brown <broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
> snd_pcm_period_elapsed(pcm);
> }
> @@ -114,6 +123,10 @@ static int bf5xx_pcm_hw_params(struct snd_pcm_substream *substream,
>
> static int bf5xx_pcm_hw_free(struct snd_pcm_substream *substream)
> {
> + struct snd_pcm_runtime *runtime = substream->runtime;
> +
> + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
> + memset(runtime->dma_area, 0, runtime->buffer_size);
Missing indentation here.
> @@ -164,8 +172,12 @@ static int bf5xx_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
> pr_debug("%s enter\n", __func__);
> switch (cmd) {
> case SNDRV_PCM_TRIGGER_START:
> - if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
> + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
> + bf5xx_mmap_copy(substream, runtime->period_size);
> + snd_pcm_period_elapsed(substream);
Calling this in the trigger callback is pretty tricky.
I guess this could be implemented without involving
snd_pcm_period_elapsed(), but rather only inside this machine driver,
if it's only the question of dummy data handling at the beginning.
> @@ -237,6 +249,21 @@ static int bf5xx_pcm_open(struct snd_pcm_substream *substream)
> return ret;
> }
>
> +static int bf5xx_pcm_close(struct snd_pcm_substream *substream)
> +{
> + struct snd_pcm_runtime *runtime = substream->runtime;
> + struct sport_device *sport = runtime->private_data;
> +
> + pr_debug("%s enter\n", __func__);
> + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
> + sport->once = 0;
> + memset(sport->tx_dma_buf, 0, runtime->buffer_size * sizeof(struct ac97_frame));
> + } else
> + memset(sport->rx_dma_buf, 0, runtime->buffer_size * sizeof(struct ac97_frame));
> +
> + return 0;
> +}
Better to clear buffers in hw_free in both playback and capture cases
(unless you have any issue against it).
The hw_free is supposed to be called anyway before closing, so you
don't need the same thing in multiple places.
As mentioned, I already pulled the patches, so please make changes
against the latest tree.
thanks,
Takashi
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