On 09/21/15 12:37, Russell King - ARM Linux wrote: > On Fri, Sep 18, 2015 at 02:06:39PM +0300, Jyri Sarha wrote: >> Add IEC958 channel status helper that gets the audio properties from >> snd_pcm_hw_params instead of snd_pcm_runtime. This is needed to >> produce the channel status bits already in audio stream configuration >> phase. > > What is the reason for doing this early? >
After some thinking, there is no good reason. It makes the codec bit more complicated, but that is not a good reason. I'll change that and use the prepare callback. This patch can be dropped. > ALSA documentation (which may be out of date) says that the hw_params > callback can be called multiple times during stream setup. Do we want > to be repeatedly programming the HDMI infoframe with different settings, > potentially confusing the attached device, or would it be better to do > it slightly later (in the prepare callback) after the parameters have > been fully negotiated? > If it is possible that hw_params() can be called multiple times, at least it does not happen very often. I wonder if it would ever happen again after a successful hw_params() call. But there is no downside in using prepare callback. I was just too much following the way ASoC codecs usually do the thing by writing everything to iron as the callbacks come in. Best regards, Jyri
