On Tue, 9 Nov 2010, Manu Abraham wrote:
On Tue, Nov 9, 2010 at 6:21 PM, Jaroslav Kysela <perex@xxxxxxxx> wrote:
On Tue, 9 Nov 2010, Manu Abraham wrote:
On Tue, Nov 9, 2010 at 5:31 PM, Jaroslav Kysela <perex@xxxxxxxx> wrote:
On Tue, 9 Nov 2010, Manu Abraham wrote:
testbox ~ # arecord -Dhw:2,0
Recording WAVE 'stdin' : Unsigned 8 bit, Rate 8000 Hz, Mono
Any idea, why saa7231_hw_params is not getting invoked ?
Your hw probably does not support directly 8-bit sample at 8000Hz, one
channel. Use 'plughw:2,0' device instead 'hw:2,0' to let alsa-lib do all
stream format conversions.
That didn't make any difference at all.
Check your code. You probably created wrong hw_ops, looking to your code:
   Â.buffer_bytes_max    = 512 * 4096,
   Â.period_bytes_min    = 8192,
   Â.period_bytes_max    = 8192,
   Â.periods_min      Â= 8192,
   Â.periods_max      Â= 8192,
It's definitely an empty configuration space.
You have buffer_bytes_max 2097152, but restricted number of periods to 8192
and period_bytes to 8192.
8192 * 8192 = 67108864 which is not less than 2097152 (and I'm not counting
the bytes for channels and formats). Bingo, the ALSA PCM code does not know
what to configure.
Decrease periods_min and probably also periods_max.
oh ! The error message was really a weird one. I can say that the
hardware can do 192 audio frames in an interrupt, whatever the frame
size is. So, what periods and period_bytes should I describe in the
configuration ?
You cannot describe this using hw_ops. Leave period bytes in good range
(192 - 1536?), periods (2-1024?) and add something like this to the open
callback:
err = snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_PERIOD_SIZE,
192, 192);
Note the difference between SNDRV_PCM_HW_PARAM_PERIOD_SIZE and
SNDRV_PCM_HW_PARAM_PERIOD_BYTES.
Jaroslav
-----
Jaroslav Kysela <perex@xxxxxxxx>
Linux Kernel Sound Maintainer
ALSA Project, Red Hat, Inc.
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