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There is a red light turned on (it seems an infrared light or optical sound) when I boot Ubuntu, and it remains always on, but not when I boot MacOS in a MacBook Pro. How can I save energy with Ubuntu as much as with MacOS and have it turned off? Also, bluetooth should always be turned off at boot time, unless you configure it to be on.

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Could you possibly add a picture of that? – saji89 May 26 '12 at 20:31
no. But it is on the left side of a macbook pro 3,1 and the icon is a headphone set – Robert May 26 '12 at 20:48
If you can see the red light, I think it cannot be called as infrared. The TV remotes have infrared LEDs and you can't see the light when they are on (unless accompanied by other LEDs in the visible spectrum). – Shashank Sawant May 26 '12 at 20:52
Sorry, I wrote it could be an optical sound something but the comment didn't went out because tags were missing and when I send it again that was lost somehow. Sometimes the tvs turn a red light on when receive the infrared. – Robert May 26 '12 at 21:00
Yes, it is the s/PDIF. You can turn it off, and the light turns off if you run alsamixer, move to s/pdif and type "M". But it will take hours and hours of horrible investigation to see how and if I can turn it off at boot time without having problems in the future when I forget what I touched, hahaha. Always the same story! – Robert May 26 '12 at 23:56

Mute the "S/PDIF" control in alsamixer and then run sudo alsactl store to make this persist across reboots.

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