[alsa-devel] my driver can't reproduce continuously

[Kuninori Morimoto]

Dear Takashi

Thank you for your comment

> My rough guess is that your pointer callback returns a wrong value.
> The pointer callback is supposed to give the currently played position
> offset in a ring buffer, and ranged from 0 to buffer_size-1.
> When the first snd_pcm_period_elapsed() is called, it should be
> (ideally) pointing at period_size, at the succeeding calls,
> period_size*2, period_size*3, then 0 again.

The criminal is my wrong understanding...
OK.

But I still have trouble now.

follows the log
------------
trigger called
hw_prt_base = 0, hw_prt = 127, appl_prt = 8192
hw_prt_base = 0, hw_prt = 255, appl_prt = 8319
(snip)
hw_prt_base = 0, hw_prt = 3845, appl_prt = 11888
hw_prt_base = 0, hw_prt = 3995, appl_prt = 12037
call elapsed                                         // 2nd call
hw_prt_base = 0, hw_prt = 4123, appl_prt = 12037
hw_prt_base = 0, hw_prt = 4272, appl_prt = 12187
call elapsed                                         // 3rd call
hw_prt_base = 0, hw_prt = 6202, appl_prt = 12288
call elapsed                                         // 4th call
hw_prt_base = 8192, hw_prt = 8192, appl_prt = 12288
<<< driver stopped here... >>
------------

when 1st buffer was send,
driver stop.
2nd trigger function isn't called.


Best regards
--
Kuninori Morimoto