[alsa-devel] [PATCH] ASoC: hdac_hdmi: Ensuring proper setting of output widget power state

[Takashi Iwai]

On Fri, 12 Jan 2018 11:37:28 +0100,
Kumar, Abhijeet wrote:
> 
> > It's better, but doesn't guarantee that the node reached the given power state.  codec_read assures that the verb is sent and the codec gives the response.  But it means only the target state gets updated, and doesn't mean that the actual state reached.
> 
> Thanks Takashi for replying. I guess, I  should make use of return value from codec_read and retry if power state is not set properly! I'll make those changes and update again. And just wondering, how does hdmi_codec_prepare() and hdmi_codec_complete() gurantee while powering up and down the afg ?

There are two power states in the codec node: the target and the
actual.  By setting the power state, the target is set, but the actual
state change may still take some time.  In such a case, you'd need to
wait until the actual state reaches.  See hda_sync_power_state() in
the hda legacy.


Takashi