Dne 30. 03. 20 v 17:09 Jaroslav Kysela napsal(a):
Dne 30. 03. 20 v 16:43 Pavel Hofman napsal(a):
Dne 26. 03. 20 v 18:59 Pavel Hofman napsal(a):
Dne 26. 03. 20 v 18:44 Jaroslav Kysela napsal(a):
Dne 26. 03. 20 v 18:19 Pavel Hofman napsal(a):
Hi,
Please how is the module params pcm_notify supposed to be used, to do what the documentation says: Break capture when PCM format/rate/channels changes?
Breaking capture side operation when the playback side changes the params is very useful, but I cannot find a way to use this param properly. When the capture side is open, the playback side cannot use a different parameter than the one currently used by the capture side (the configuration space is limited)
Really? Then it's a bug introduced by the last changes.
If you look to sources:
if (get_notify(dpcm)) runtime->hw = loopback_pcm_hardware; else runtime->hw = cable->hw;
And:
if (!(cable->valid & ~(1 << substream->stream)) || (get_setup(dpcm)->notify && substream->stream == SNDRV_PCM_STREAM_PLAYBACK)) params_change(substream);
So the functionality should be there.
I am using older kernels (4.15 and 3.16), but this is an old functionality.
modprobe snd-aloop pcm_substreams=1 pcm_notify=1,1
Please is there any way to solve this issue? Thanks a lot for your patience.
I can reproduce this. It appears that the driver should be fixed, but I don't have a solution at the moment.
It seems that 898dfe4687f460ba337a01c11549f87269a13fa2 from Takashi broke this functionality (tied the cable parameters more strictly, so the playback cannot set freely own parameters for the pcm_notify=1 case). We need to find another way to detach capture stream in this case.
Thanks a lot for your effort. I am afraid I cannot help with such design-level task.
BTW the sound design of snd-aloop allows reliable operation at 20MHz samplerate, it took just a period_max param change https://www.diyaudio.com/forums/equipment-and-tools/349239-support-samplerat... I will ask for considering a substantial samplerate range extension in a separate post :-)
Thanks again.
Best regards,
Pavel.