[CML][PM] White noise when being runtime suspended after playback

Summary:
when playback using alc5682 codec on cometlake, there is a about 2s white noise when entering runtime suspend.

Test steps:

Play some music, eg.
aplay -vv -Dhw:0,0 -c2 -d2 48California_Dreaming.wav
when it ends, check the runtime status
cat /sys/bus/pci/devices/0000:00:1f.3/power/runtime_status
The noise occurs when entering runtime suspended.
However, this noise only happens in suspending and if we trigger new playback, there will be no noise during playback.

Test env:
sof cml-001-drop-stable: 1f5a965
kernel topic/cros-sof-v4.19: f69d618
tplg: sof-cnl-rt5682.tplg

noise file: noise.zip

MCLK is turned off in runtime suspended. However, sof enter runtime suspend before DAPM off. In other word, MCLK is turned off before codec is powered off. And noise will occur in that period.

I believe we will have to make the MCLK/BCLK controllable from the machine/codec driver. This is a feature that was implemented in the cAVS driver and that we know we need to avoid issues due to clock transitions, but haven't done any work on. There are some fields in the IPC that could be used to leave the MCLK on, but they are not set. see SOF issue #629 thesofproject/sof#629 We'd also need the pm_runtime to suspend the DSP when there is no need for any clocks. In other words it's not going to be fixed overnight.

@wwittbrx

@wwittbrx bringup Hatch. thank you Wojtek.

We just checked flow from topic and we haven't repro. There is no "white noises" after end of the playback on each time.

Configuration:
Platform: Hatch CML
kernel: cros-sof-v4.19 / 8492020d5967 + PR#651 applied
FW: cml-002-drop-stable / dcd825b
tplg: sof-cnl-rt5682.tplg

Checked also on WHL RVP and there is also no reproduction with "while noises":
kernel: cros-sof-v4.19 / 8492020d5967 + PR#651 applied
FW: cml-002-drop-stable / dcd825b
tplg for hda: sof-hda-generic.tplg

@emilchudzik

@emilchudzik Did you test it by headphone?

No, I tested it by hdmi.
On headphone I haven't any sound although there is no errors in dmesg log and aplay show playback progress without any issues. I haven't went deeper for debugging it yet - I will try it again with deeper analysis and I will give a feedback.

@bardliao

I just tested flow from topic on headphone (thanks to @bardliao to help configure alsamixer).

On SSP0 (connected headphones) I have this observation:

I play 5 seconds: aplay -vv -Dhw:0,0 sine.wav -d5
after that I hear about 1 seconds of silence
then I hear about 1 seconds of something like mic is opened, but this is not "uggly white noise", but just something like "simple noise from mic"

Here is a dmesg from start aplay to going suspended
dmesg.txt

@xun2z

@xun2z is this issue still relevant? It's been 24 days without update.

@plbossart

@plbossart We still have this issue. Bard says he's trying to set a ignore_pmdown_time flag, which can shut down rt5682 immediately after playback. I'll look into it and help to check with Bard.

close since #741 is the fix

coresight: Fix DEBUG_LOCKS_WARN_ON for uninitialized attribute

reset: whitespace fixes

net: bridge: keep ports without IFF_UNICAST_FLT in BR_PROMISC mode

soc: imx8m: Probe the SoC driver as platform driver

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[CML][PM] White noise when being runtime suspended after playback #603

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[CML][PM] White noise when being runtime suspended after playback #603

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bardliao commented on Jan 30, 2019

plbossart commented on Jan 30, 2019

emilchudzik commented on Feb 25, 2019

bardliao commented on Feb 26, 2019

emilchudzik commented on Feb 26, 2019

emilchudzik commented on Feb 28, 2019

plbossart commented on Mar 24, 2019

xun2z commented on Mar 25, 2019

xun2z commented on Apr 2, 2019

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