[alsa-devel] [PATCH 0/3] ALSA: pcm: add tracepoints for PCM params refinement

Takashi Iwai tiwai at suse.de
Wed Jun 7 10:50:29 CEST 2017


On Wed, 07 Jun 2017 10:38:24 +0200,
Takashi Sakamoto wrote:
> 
> On Ju 7 2017 17:09, Takashi Iwai wrote:
> >>>> The second field represents id of each rule applied to the runtime, and
> >>>> the total number of rules added to the runtime. Basically, when the rule
> >>>> is applied to the runtime, these events are probed, but lines with id 0
> >>>> are exceptions. They're application of constraints to the runtime.
> >>>>
> >>>> The third field is name of parameter in the runtime. The rest fields
> >>>> depends on type of the parameter (mask/interval).
> >>>>
> >>>>
> >>>> In ALSA PCM core, runtimes get 22 (or 21) rules as a default. In a below
> >>>> sample, the 21st rule is added by driver (snd-soc-imx-ssi.ko). The rest is
> >>>> added by snd-pcm.ko. In detail, please see 'snd_pcm_hw_constraints_init()'
> >>>> and 'snd_pcm_hw_constraints_complete()' in 'sound/core/pcm_native.c'.
> >>>>
> >>>> hw_interval_param: 0,0,0,0 019/023 PERIOD_TIME 0 0 [0 4294967295] 0 0 (166 4095875]
> >>>> hw_interval_param: 0,0,0,0 020/023 BUFFER_TIME 0 0 [0 4294967295] 0 0 (333 4096000]
> >>>> hw_interval_param: 0,0,0,0 021/023 PERIOD_SIZE 0 1 [16 32767] 0 1 [16 32766]
> >>>> hw_interval_param: 0,0,0,0 022/023 BUFFER_BYTES 0 1 [128 65536] 0 1 [128 65536]
> >>>> hw_interval_param: 0,0,0,0 023/023 RATE 0 0 [8000 96000] 0 0 [8000 96000]
> >>>> hw_mask_param:     0,0,0,0 001/023 FORMAT 00000000000000000000001000000044 00000000000000000000001000000044
> >>>
> >>> Could you add these explanations in Documentation?  The cover letter
> >>> is gone at merging.
> >>
> >> Hm. Could I postpone the task for my later work in this development
> >> period? Text writing takes me a bit time, but I have patches for the
> >> rest of my RFC and firewire stack.
> >
> > It's fine if you can promise to submit the document patch in this
> > development cycle :)
> 
> I promise.

Good to hear, I merged your three patches now.  Thanks!


Takashi


More information about the Alsa-devel mailing list