Hi Amadeusz
Thank you for your research
it feels like it works around the fact that some DAIs didn't had set channels_min properly, which will of course not work with snd_soc_dai_stream_valid(). Perhaps if we want to remove this flag we should just set channels_min everywhere where we want to have playback or capture and just remove flag?
Interesting. It seems detail usage was updated from original to emphasize checking.
For me, I have no objection about this.
Similar story with playback_only and capture_only, which was introduced in two patch series to remove unsupported FEs from list of available ones:
(snip)
I feel like if driver author knows that one of directions should be unused they should just set min_channels to 0 to disable it on either BE or FE DAI (personally I would prefer FE DAI in most cases).
Unfortunately, this is not good idea, IMO. Because min_channels is set at snd_soc_dai_driver driver, and almost all drivers are using same settings for all device.
For example if you use same 4 x Codecs, but want to use playback_only on 1 Codec, min_channels = 0 will be used on all Codecs. Same things can be happen on CPU side, too. So we want to have xxx_only option, IMO.
Thank you for your help !!
Best regards --- Renesas Electronics Ph.D. Kuninori Morimoto