On Fri, 13 Jun 2008, Takashi Iwai wrote: > - Add some new API functions, I would prefer to extend the current API than to change meaning of hw_ptr to handle extra latencies. > * To give the accuracy of the position inquiry (optional) > > This requires some new kernel <-> user-space stuff. > * To query the known latency > > Ditto, or we may reuse snd_pcm_hw_params_fifo_size()? Yes, fifo_size was designed to announce possible extra latency to applications. > * To query the position being played (optionally) > > This can be simply hwptr + latency. > > - Don't change snd_pcm_delay(). Keep as is now. > > > About the period model -- it's a bit more tough problem. > I once already made a patch to allow user-apps to use a system timer > for more flexible period settings. But, it was for very old version > of ALSA. Better to write from the scratch again... I think that the current PCM API concept is tightly period based. You cannot change it easily. It would be probably better to move to "byte-stream" in next revision of PCM API. Jaroslav ----- Jaroslav Kysela <perex@xxxxxxxx> Linux Kernel Sound Maintainer ALSA Project, Red Hat, Inc. _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
