At Fri, 6 Jun 2008 20:46:12 -0400, Lee Revell wrote: > > On Fri, Jun 6, 2008 at 3:54 PM, Christian Morales Vega > <cmorve69@xxxxxxxx> wrote: > > snd_pcm_avail_update() documentation says: "Using of this function is > > useless for the standard read/write operations. Use it only for mmap > > access. See to snd_pcm_delay." > > > > snd_pcm_delay() documentation says: "Note this function does not > > update the actual r/w pointer for applications. The function > > snd_pcm_avail_update() have to be called before any begin+commit > > operation." > > > > My english is far from perfect, and so the problem can be that I > > missunderstood the docs but: > > 1- "Using of this function"? Should not be "Use of this function"? > > I would just say "This function is useless for...". Patch please ;) > > 2- Is snd_pcm_avail_update() really useless when not using mmap? > > The pcm.c example referenced right below that comment would indicate otherwise: > > http://www.alsa-project.org/alsa-doc/alsa-lib/group___p_c_m.html#g41ca534658076885d9b077ad674750cd > > > I have a SB Live! where snd_pcm_delay() always returns the correct > > value, without any need for snd_pcm_avail_update(). But the same code > > in the same machine with an hda-intel AD1988 needs a call to > > snd_pcm_avail_update() before snd_pcm_delay() to give the correct > > result. Without it snd_pcm_delay() always returns the value that *was* > > correct in the last snd_pcm_writei() call. > > > > So should the "application frame position" be always updated, or only > > in read/write operations? In the first case AD1988 fails, in the > > second case perhaps SB Live! is making too mucho work ;-) > > Is this with the latest ALSA HG sources? > > The SBLive driver is better working and more mature, so I'd presume it > to be correct. Takashi-san? It's unlikely a driver issue but an incompatibility of dmix, I guess. But still I don't figure out why this happens. The hwsync is done at each snd_pcm_dmix_delay() call (as long as slowptr is set, and it's so as default). So, there shouldn't be any difference... What happens if you use "hw" or "plughw"? Takashi _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
