At Thu, 17 Dec 2009 16:31:08 +0900, jassi brar wrote: > > On Thu, Dec 17, 2009 at 4:02 PM, Takashi Iwai <tiwai@xxxxxxx> wrote: > > At Thu, 17 Dec 2009 15:00:02 +0900, > > jassisinghbrar@xxxxxxxxx wrote: > >> > >> From: Jassi Brar <jassi.brar@xxxxxxxxxxx> > >> > >> The check for at least 'avail_min' available data before calling wake_up > >> doesn't always hold good as it does not guarantee callbacks at each periodic > >> interrupt. > > > > Well, avail_min can be greater than period_size. And, avail_min won't be > > less than period size. > > > > For example, when avail_min = 2.5 x period_size, the driver wakes up > > in periods like 3, 2, 3, 2, ... > correct, but if we ensure wake_up's after each period and let the 'sleepers' > track if the data available is enough or not, we will have more fine grained > control. > The point is:- Waking up _after_ avail_min is working, but does waking up before > avail_min(but at period boundary) break the system? PulseAudio may complain :) > >> An example of such situation is snd_pcm_lib_read1/write1 consuming some space > >> of the period and going to sleep from wait_for_avail_min upon syncing with > >> the DMA pointer. Clearly just the remainder of period size is needed, but > >> wake_up is called only after _two_ periodic interrupts from that point. > > > > In that case, the original behavior is correct. > going by current implementation, that is correct, but is that desirable? Correct = working as designed. Takashi _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
