[alsa-devel] hw_ptr accuracy with intel8x0 -> PulseAudio issue

[Raymond Yau]

2009/12/10 pl bossart <bossart.nospam at gmail.com>

> Takashi,
> I tested with .periods_min=2 and reduced the period_max by half. The
> underruns reported by PulseAudio are no longer present with this
> modification.
>


why did you reduce periods_max by half since the driver should still support
1024 periods of 32 bytes when you set periods_min = 2 ?

Is it period_bytes_max by half ?

static struct snd_pcm_hardware snd_intel8x0_stream =
{
    .info =            (SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_INTERLEAVED |
                 SNDRV_PCM_INFO_BLOCK_TRANSFER |
                 SNDRV_PCM_INFO_MMAP_VALID |
                 SNDRV_PCM_INFO_PAUSE |
                 SNDRV_PCM_INFO_RESUME),
    .formats =        SNDRV_PCM_FMTBIT_S16_LE,
    .rates =        SNDRV_PCM_RATE_48000,
    .rate_min =        48000,
    .rate_max =        48000,
    .channels_min =        2,
    .channels_max =        2,
    .buffer_bytes_max =    128 * 1024,
    .period_bytes_min =    32,
    .period_bytes_max =    128 * 1024,
    .periods_min =        1,
    .periods_max =        1024,
    .fifo_size =        0,
};