On 5/15/21 12:04 AM, Chris Caudle wrote: > Does anyone know if jackd (or the Ardour ALSA backend) can be forced to > use interleaved mode? Ardour's ALSA backend is based on zita-alsa-pcmi and does support interleaved mode, but there is no switch to force it on. It cannot be forced since it requires at least 2 parameters (offset and stride) the first of which may differ every cycle depending on where memory is mapped to. Relevant methods are snd_pcm_mmap_begin() [1] which provides the info and pointers in a snd_pcm_channel_area_t [2] struct. > but apparently jackd and Ardour try to open in non-interleaved mode. Ardour indeed tries SND_PCM_ACCESS_MMAP_NONINTERLEAVED first and falls back to SND_PCM_ACCESS_MMAP_INTERLEAVED (and SND_PCM_ACCESS_MMAP_COMPLEX) if the former fail. One could add an option to override this configuration behavior, but that would only be useful for driver development/debugging. -- robin [1] https://www.alsa-project.org/alsa-doc/alsa-lib/group___p_c_m___direct.html [2] https://www.alsa-project.org/alsa-doc/alsa-lib/structsnd__pcm__channel__area__t.html
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