At Wed, 22 Aug 2007 16:08:49 -0500, Timur Tabi wrote: > > Takashi Iwai wrote: > > > The buffer allocation in prepare callback would actually do work. > > I've never mentioned that it doesn't work. It's just not > > recommended, simply because the prepare is called more often than > > hw_params even without changing the parameters. > > What is the driver supposed to do on the second call to .prepare()? In other > words, what is the point of calling it multiple times in a row? Once my > driver is prepared to start, how could it become more prepared? The purpose of prepare callback is to make the PCM stream ready to start. (The trigger callbacks are supposed to be just triggering, not preparing the stream.) Usually, once after the PCM is triggered, the registers are no longer as same as the beginning. If you want to stop and restart the stream, you'll very likely to reset the registers again. That's why prepare is called again. (Or, your driver is always go-or-die? :) Takashi _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
