From mboxrd@z Thu Jan  1 00:00:00 1970
From: Takashi Iwai <tiwai@suse.de>
Subject: Re: [PATCH] ASoC: hdac_hdmi: Ensuring proper setting
	of output widget power state
Date: Fri, 12 Jan 2018 12:09:00 +0100
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To: "Kumar, Abhijeet" <abhijeet.kumar@intel.com>
Cc: "alsa-devel@alsa-project.org" <alsa-devel@alsa-project.org>, "Koul,
 Vinod" <vinod.koul@intel.com>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "Singh,
 Guneshwor O" <guneshwor.o.singh@intel.com>, Liam Girdwood <lgirdwood@gmail.com>, Mark Brown <broonie@kernel.org>, "Kp,
 Jeeja" <jeeja.kp@intel.com>, "Tayal, SandeepX" <sandeepx.tayal@intel.com>, "Prusty, Subhransu S" <subhransu.s.prusty@intel.com>
List-Id: alsa-devel@alsa-project.org

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