Strange sound fade off as soon as I plug a headpone
 

Hello there,

I have a strange issue with my sound system under linux. Everything works well until I plug my headphone in. Then I can heard the sound slowly fading off, and then no sound anymore, even if I unplug the headphone! The only way to get it back is to reboot my computer!

The result of alsainfo can be read there: http://pastebin.ca/1218037

I'm under FEDORA core 8, and I have the same behaviour with the last kernel (2.6.26.5-28).

Is there a way to reset alsa without rebooting the system, since removing the modules one by one is really a pain in the ass!

Can somebody give me an advice, where to look at?

I need music so please don't let me in the dark...

Thanks

it is a long shot, but try "alsactl store/restore" commands.

Thanks for your reply,
I didn't says that I've already tried alsactl store /restore without success (I mean no sound after alsactl), and playing with alsaunmute and alsamixer don't bring me back my music...

Does it only happens with Fedora ?
Or do you use other distros too ?
If so what happens there ?
If you change the loudspeaker by a headphone you change load on the amplifier if it has no effect with the other distros than it has nothing to with load change and than it is a Fedora problem

My box is a linux only box, she's allergic to other OS's, and I don't want install another OS just to try it...
I'm not sure to understand what you mean there. By the way, I plug the headphone in its own plug, and when it's plugged, the loudspeaker automagicaly mute, as expected. And if I unplugged the headphone, normally the sound must come back to the loudspeakers. The last time I try this, there's maybe 2 or 3 weeks, it works...

Well a loudspeaker has a resistance somewhere between 4 to 8 Ohm
By headphone it depends totally on the way the headphone is constructed
One of the ways is to make a high impedance headphone , most amplifiers can deal with this type of headphones .
A other type of headphone is a electro dynamic headphone , the resistance
of this type of headphone is somewhere between 0 - 100 Ohm a good amplifier can deal with type too
There are also headphones that works as a compromise of this to types

OK, thank you for the electronic tutorial, but, my computer have an output for headphones, which is different than the output for loudspeaker... More over, while it's true that loudspeaker have a low impedance input, remember that what you plug onto your computer is amplified loudspeaker, so their input are most likely a high impedance input...

It's certainly a software issue, but I don't know alsa very well, and I have to search in that direction, if you know how alsa deal with the headphone detection, I'll be happy to have some advice for that.

Do not use a headphone , but Kmix >switches there is a option headphone
do not know what it does .