On 20/09/2019 11:50, Marc Gonzalez wrote: > One more concern popped up: if the audio stream changes mid-capture > (for example, a different TV program uses different audio settings), > then I would detect this in the eARC receiver, but it's not clear > (to me) how to propagate the info to the DSP... > > I'm not even sure when the HW params actually get applied... > Is it for SNDRV_PCM_IOCTL_PREPARE? SNDRV_PCM_IOCTL_START? I enabled debug logs in the sound layer: echo "file sound/* +fpm" > /sys/kernel/debug/dynamic_debug/control and sprinkled dump_stack() in several driver callbacks. When I run 'tinycap /tmp/earc.wav -t 10 -r 44100 -b 32' I see the open/SyS_openat call and the capture ioctl call which together generate calls to 1) dpcm_fe_dai_open 2) dpcm_fe_dai_hw_params 3) dpcm_fe_dai_prepare 4) dpcm_fe_dai_trigger But everything looks "synchronous", as in "reaction to user-space commands". I don't see how "asynchronous" events are dealt with, such as the stream params changing while a capture is active? Regards. _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx https://mailman.alsa-project.org/mailman/listinfo/alsa-devel
