On Wed, 25 Jul 2018 23:52:36 +0200, Rob Duncan wrote: > > Is it required that all available data has been committed between calls > to snd_pcm_ioplug_avail_update() on an IO plugin capture stream? Yes, the capture data is committed. The snd_pcm_ioplug_hw_ptr_update() should have reported the amount of data the slave PCM can actually transfer. Hence the transfer call thereafter must fulfill the whole requested data. The capture in ioplug is a sort of mmap emulation. On real hardware, the mmap data is already committed before update_avail is called, update_avail just follows the already committed amount. In the emulation mode, it's other way round; the data is committed at the point hwptr is update, i.e. avail_update is called. Takashi > If this is not a requirement then there can still be uncommitted data in > the mmap after the current appl_ptr. This data will get overwritten by > the transfer call. > > If it is a requirement then snd_pcm_rate_avail_update() seems to be > doing the wrong thing, because it only commits in units of the period > size, which means that there could be a partial period left in the mmap. > > Can someone clarify what the contract is for these calls? > > Thanks, > > Rob. > _______________________________________________ > Alsa-devel mailing list > Alsa-devel@xxxxxxxxxxxxxxxx > http://mailman.alsa-project.org/mailman/listinfo/alsa-devel > _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
