[alsa-devel] Question about aux device

29 May 2019


      Hi ALSA ML
I wonder about aux device probe method.
Does someone know about it ?
(1)
snd_soc_instantiate_card() binds all (normal) components by
soc_bind_dai_link()
~~~~~~~~~~~~~~~~~
(2)
And initialize/probe all binded (normal) components after that.
Here, in this operation, it will calls soc_probe_component().
                                       ~~~~~~~~~~~~~~~~~~~
(3)
After that, auxiliary component is probed by using soc_probe_component()
                                                   ~~~~~~~~~~~~~~~~~~~
(4)
And, auxiliary component is binded by soc_bind_dai_link() after that.
                                       ~~~~~~~~~~~~~~~~~
static int snd_soc_instantiate_card(struct snd_soc_card *card)
    {
    	...
    	/* probe normal components here */
    	for_each_card_prelinks(card, i, dai_link) {
(1)=>			ret = soc_bind_dai_link(card, dai_link);
    		if (ret != 0)
    			goto probe_end;
    	}
    	...
    	/* probe all components used by DAI links on this card */
    	for_each_comp_order(order) {
    		for_each_card_rtds(card, rtd) {
(2)=>				ret = soc_probe_link_components(card, rtd, order);
    			...
    			}
    		}
    	}
/* probe auxiliary components */
(3)=>		ret = soc_probe_aux_devices(card);
    	...
for_each_card_links(card, dai_link) {
    		...
(4)=>			ret = soc_bind_dai_link(card, dai_link);
    		...
    	}
}
1st question is it seems the order of (1)/(2) and (3)/(4) are different.
are there some reason about it ? or no reason ?
2nd question is can we merge these ? (1)+(4) and (2)+(3).
Or do we have some reason ?
For example (3)/(4) need to be called after xxxx.
Thank you for your help !!
Best regards
---
Kuninori Morimoto