At Mon, 14 Jul 2008 16:25:04 -0500, Timur Tabi wrote: > > Takashi Iwai wrote: > > > Right now there is no "elegant" way for this, unfortunately. > > A common way many drivers use is to remember the rate of the first > > stream, then add it to hw_constraint of the secondary streams. > > Can you give me an example of a driver that does this? I can't seem to find one. In a simple case, you don't need hw_constraint functions. Just override the corresponding fields of runtime->hw in open callback. For example, pci/via82xx.c sets the current rate value to runtime->hw.rate_min/max if there is another stream. More complicated examples are found in echoaudio driver. > > But, this could be also a bit racy (unavoidable due to its design) > > although practically it seems working. > > I've been trying to implement this, but I'm not sure how. I have a couple > questions: > > 1) Which snd_pcm_hw_constraint_xxx function should I use to specify a sample > rate or sample size constraint of a single number? I'm thinking > snd_pcm_hw_constraint_list(). The simplest way is to override the runtime->hw parameter as mentinoed in the above. > 2) Where should I be calling this function? In my _hw_params() function? Usually these hw_constraints are set in open callback. > What > I would like to do is require the constraint to be enforced only when a stream > is already playing. That is, if playback is paused, then the capture stream can > set any sample rate it wants. Is this doable, or just too complicated? This is a scenario above a simple hw_constraint. This would be also confusing to apps in many cases. Takashi _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
