Realtek audio Optical output prevents PC going into sleep mode

Dear Forum,
Appreciate your feedback on the below problem I'm facing:
My desktop will not go into sleep mode after the set time. Forcing sleep mode (sleep button) works OK.
Using the "Windows 7 insomnia" information found in various fora, the "powercfg -requests" command and quite some time (...), the issue boiled down to the "An audio stream is currently in use" message from said command originating from the Realtek High Definition audio driver. Further digging revealed that if I would disable the optical SPDIF output in sound/playback devices, the error message from "powercfg -requests" would disappear and the PC would go into sleep mode as intended. Strangely enough, the 'speakers' and the 'Realtek digital output' (this is the non-optical digital output) can stay enabled for the sleep mode to work OK.

Question: how can I keep also the optical digital audio output enabled AND enjoy the power saving effect from Sleep mode?

Some background: Windows 7 Ultimate, Asus P8P67EVO mobo with Realtek audio, latest audio drivers, using both 'speaker' and 'optical' sound output to feed the PC speakers (using analog audio) as well as the audio system (using digital optical audio). The optical connection to the audio system effectively avoids any ground-loops and hence no hum/noise. If I would use "powercfg" to ignore the audio driver 'in use' information - which is often an effective workaround - the PC would also go into sleep mode when just playing audio. PS: if this is not the right/best forum for this question, please let me know.

What is your setting here,

Roy

Hi Roy,

Thanks for your reply! I came across those settings. See attachments (capture and capture2).

During testing I had set both time-outs to 1 minute. Also tried the Advanced Power setting on multi media to "Allow the computer to sleep" next to several other variants. However, the sleep mode-after-set-time would only happen when Powercfg - requests would report "None" for Display, System as well as Awaymode (capture3).
In fact, status as per capture up to capture3 results in working timed sleep mode.
Note that to achieve this, I need to disable the Realtek Digital Output(Optical) output from my sound system (capture4).
However, the typical situation I encounter with the optical output enabled has the following reply from powercfg -requests:

SYSTEM:
[DRIVER] Realtek High DefinitionAudio(HDAUDIO\FUNC_01&VEN_10EC&DEV_0892&SUBSYS_10438469&REV_1003\4&36802a14&0&0001)
Anaudio stream is currently in use.

Which is gone as soon as I disable the optical output.

Yet, these kind of topics often create some 'blindness for the obvious' at my end, hence I appreciate your suggestions!

Hi Forum,
Please see https://social.technet.microsoft.com/Forums/en-US/bda59ea8-550a-4bc2-93d7-53969a30d1bf/spdif-optical-output-prevents-pc-going-into-sleep-mode?forum=w7itprogeneral where I addressed the same issue. A practical workaround was suggested which proved OK in my situation.