On 17/03/2021 17:00, Amadeusz Sławiński wrote:
On 3/17/2021 4:16 PM, Srinivas Kandagatla wrote:
Hi All,
Am trying to load a FrontEnd/pcm dai definition from ASoC topology
however I hit a catch 22 situation here. Topology is loaded as part of
component probe() but component probe is only called as part of
sound-card bind().
Any pointers on how is this supposed to work?
Thanks,
srini
Hi,
I would say I partially described how it works, when writing topology
kunit tests, here is link to cover letter:
https://lore.kernel.org/alsa-devel/20210120152846.1703655-1-amadeuszx.slawinski@xxxxxxxxxxxxxxx/
Thanks for the link.
To sum it up, there is no predefined order in which component and card
should be created. After each one of them is created ASoC tries to
rebind everything together and it should call component probe if
everything connects correctly.
Probe defer is not the issue here. All the relevant components are
successfully probed, however the FE dais did not get chance to register
from topology due to the below situation.
I'm not sure what problem you are seeing, but if you look at topology
test cases I only define BE in it, no FEs. So I guess you can look at it.
This will work because BE dais are not defined in topology file.
Am trying to load FE dais from topology file along with the graph
definition.
Ex:
Lets say we have a dai link in soundcard which has cpus->dai_name
pointing to an FE dai ("MultiMedia1") available in topology file.
In this situation, sound card will be probed defered unless
"MultiMedia1" dai is registered! However "MultiMedia1" dai can only be
registered when the ASoC component("X") responsible for loading/reading
tplg firmware is component->probed. This component("X") is only
component->probed as part of soc_probe_link_components() during card bind.
So we are in catch 22 situation where in dai will not be registered
because soc_probe_link_components() will not be called as dai is not
registered.
You can also look at skylake (sound/soc/intel/skylake) or SOF
(sound/soc/sof/) driver code which are real use cases of topology.
skylake and SOF code have pcm part which creates component and registers
probe function responsible for loading topology. Separate part are
machine drivers which create card (sound/soc/intel/boards).
Sure, I will dig in and see if I can find anything interesting :-)
--srini
