[alsa-devel] Can Realtek HD-A codec ALC282 support D3cold?

Lin, Mengdong mengdong.lin at intel.com
Mon Apr 15 09:57:44 CEST 2013


We want to put an idle HD-A codec into D3cold for more power saving and preparation for being power gated. The Realtek ALC282 is used in our test.
Could anyone help to confirm whether ALC282 can support D3cold or not?

I'm told that ALC282 can support D3cold. But my test shows it cannot.

At first, ALC282 HW does not report that it can support D3cold.
Its parameter "Supported Power States" returns 0xc000000f, means it only supports:  EPSS, CLKSTOP, D3hot, D2, D1 and D0.
Is this a just mistake in reporting the bit, or D3cold is not supported all?

Then when I explicitly set the audio function group to D3cold by verb 0x705, and then get its power state after 200ms by verb 0xf05,
The codec response is 0x00000000: No PS-Error, both PS-Act and PS-set is D0. So it seems the command to D3cold is not processed by codec HW at all.

Is there someone from Realtek or with experience on ALC282 here can share some information about this issue?

Many thanks

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