On 1/31/2011 4:22 PM, Marcus D. Leech wrote:
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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