>>
>> audio_alsa_source[hw:2,1]: get_period_size failed: Invalid argument
>>
>> I think the clue is in the above.
>>
>> It looks like the device-specific driver for this hardware doesn't
>> contain the "PERIOD_SIZE" parameter
>> in the configuration description for the hardware, and Gnu Radio
>> uses that information for buffer
>> planning purposes (using it for set_output_multiple() ). Not
>> clear whether there's a fix or not, and
>> whether the fix belongs in Alsa or Gnu Radio.
>>
>
> Would this keep Gnu Radio from using the card at 1792000 but still
> allow 896000?
>
> Using this in config.conf
> [audio_alsa]
> verbose = true
>
> And setting samp_rate to 896000
>
> GRC returns this-
> PCM name: hw:1,1
> Access types:
> MMAP_INTERLEAVED YES
> MMAP_NONINTERLEAVED NO
> MMAP_COMPLEX NO
> RW_INTERLEAVED YES
> RW_NONINTERLEAVED NO
> Formats:
> S8 YES
> S16_LE YES
> Number of channels
> min channels: 1
> max channels: 1
> 1 channels YES
> Sample Rates:
> min rate: 119466 (dir = 1)
> max rate: 1792000 (dir = 0)
> 8000 NO
> 16000 NO
> 22050 NO
> 32000 NO
> 44100 NO
> 48000 NO
> 96000 NO
> 192000 NO
>
> So I would think that Gnu Radio should know about the higher rate??
> The flowgraph does execute at 896000.
>
> But, if I set samp_rate to 1792000, I get the get_period_size failed:
> Invalid argument error.
>
> Just trying to understand this stuff- still in the steep part of the
> learning curve.
>
> George
>
>
I suspect the answer lies in the bt87x kernel driver for Alsa and not in
Gnu Radio per se. Could be wrong, I haven't looked
that deeply into the audio-alsa code.
--
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org
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