Problem resolved. In the poll buffer thread which emulates the hardware interrupt it was tracking the application
pointer (appl_ptr). When I switched to looking at the hw_ptr things worked with dmix.
Daniel
Daniel Cardenas wrote:
> Results of my latest debug: dmix is reporting an error in routine
> snd_pcm_dmix_sync_ptr() complaining that the pipe is
> in the running state. Here is a snippet of code:
>
> Daniel Cardenas wrote:
>> Takashi Iwai wrote:
>>> At Thu, 8 Feb 2007 10:44:10 -0800,
>>> <daniel.car@xxxxxxx> wrote:
>>>> Hi,
>>>>
>>>> I'm working on an unannounced SOC audio driver on an ARM system.
>>>> I have a problem were audio works fine with out dmix, but when I try
>>>> to use dmix, no audio data gets to the driver.
>>>> The dmix plug-in does work when attaching external usb audio
>>>> device. Trying to use dmix so that more then one application can
>>>> generate audio simultaneously.
>>>>
>>>> If I try with version 1.0.11 of ALSA the audio driver doesn't
>>>> receive any data after the snd_pcm_period_elapsed() function call.
>>
>> Actually it is before or after.
>>
>>>
>>> So, actually it's a problem of driver / alsa-lib hw layer rather than
>>> dmix? You can get more verbose messages by setting LIBASOUND_DEBUG
>>> variable. See alsa-lib/NOTES for details.
>>
>> I set the environment variable and I did not see additional output.
>> For version
>>
>>
>>>
>>>> Here is how the driver is set up:
>>>> static snd_pcm_hardware_t snd_oloriver_playback_hw = {
>>>> .info = (SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_INTERLEAVED |
>>>> SNDRV_PCM_INFO_MMAP_VALID),
>>>> .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 = 65536,
>>>> .period_bytes_min = 32768,
>>>> .period_bytes_max = 32768,
>>>> .periods_min = 2,
>>>> .periods_max = 2,
>>>
>>> My rough guess is that the buffer and period size constraints are too
>>> restrictive. You can try to pass the exact period/buffer sizes to
>>> aplay via --period-size=8192 --buffer-size=16384 options.
>>>
>>> Takashi
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