Kai Vehmanen wrote: > > On Thu, 21 Feb 2002, Abramo Bagnara wrote: > > >>> if (avail > pcm->buffer_size) > >> Yes, this condition is faulty. It should be 'avail >= pcm->stop_threshold'. > > - if avail > buffer_size this means either played garbage (playback) or > > overwritten samples (capture). The return of an error is perfectly > > sensible (also because the value returned would not have any sensible > > meaning). > > Hmm, the mmap semantics of stop_threshold should be similar to the > read()/write() API.
And this was already true. If you use mmap or read/write is irrelevant wrt stream stop in XRUN state. > The functions in alsa-kernel/core/pcm_lib.c seem to take care that > read/write don't access outside the buffer area. On the other hand it is > possible to process more bytes than buffer_size with one call. > > Similarly the short pcm mmap example in the ALSA API documentation > (alsa-lib/src/pcm/pcm.c), can also handle situations where avail_update() > reports more frames than buffer_size (as can happen after Jaroslav today's > changes). It always processes period_size at a time. > > It's also true that without the change, stop_threshold didn't work > properly with mmap access. ??? Why you think that? > > Yes another pov is that Jaroslav changes might cause trouble to some Not "might", the change already now break all plugins! > applications (at least jackd will require patching as it sets > stop_threshold to UINT_MAX - not a big thing in this case). Hmm, could > this cahnge result in accessing illegal memory areas in some > situations...? > > > - the insertion of SND_PCM_IOCTL_XRUN is a nonsense, as the application > > has explicitly asked to not stop the stream when xrun happens. > > It's only called if stop_threshold is set to buffer_size or lower (-> app > _has_ asked to stop if xrun occurs). The point is that alsa-lib will stop the stream also when application has asked to *not* do that. I call this a _broken_ behaviour, don't you? That apart perhaps to have a snd_pcm_xrun call (to couple with snd_pcm_drop and snd_pcm_drain) might be useful (who knows, I don't believe, but...) -- Abramo Bagnara mailto:[EMAIL PROTECTED] Opera Unica Phone: +39.546.656023 Via Emilia Interna, 140 48014 Castel Bolognese (RA) - Italy ALSA project http://www.alsa-project.org It sounds good! _______________________________________________ Alsa-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/alsa-devel
