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swiergot

Member

From: Kraków, Poland

Registered: 2005-01-08

Posts: 145

[SOLVED] Strange behaviour of audio driver

Hi,

I'm having a very strange problem with sound on my Asus laptop. It started yesterday when I rebooted the machine after five days of running. During that time I didn't upgrade any important package nor did I change any configuration (if memory serves).

So yesterday when I logged into KDE I got a message saying that audio devices were gone. When I tried mplayer to see if it's a KDE thing, it complained about non-existing sound card and it was actually true as there were no sound related files under /dev, even though all audio modules were loaded. I removed all of them and modprobed snd-hda-intel. KDE immediately detected audio devices and sound was back everywhere.

Now the funny part. I rebooted again and before logging into KDE, I checked the sound in a console, no luck. I repeated what I did previously to bring the sound back, that is rmmod&modprobe. But this time it didn't work. Then I logged into KDE and tried again, guess what, sound was back!

So what is it that KDE is doing? At the end exactly the same modules are loaded, the only difference is that hd-audio0 process is not running when the driver is loaded without KDE.

Any ideas?

Last edited by swiergot (2009-11-22 08:37:43)

swiergot

Member

From: Kraków, Poland

Registered: 2005-01-08

Posts: 145

Re: [SOLVED] Strange behaviour of audio driver

(if memory serves)

Well, it doesn't. To make things worse, my sight is not good either. The devices are present in /dev and I did change configuration.

It turned out to be a permissions problem. I was doing some cleaning in /etc, getting rid of *.pacnew and *.pacsave and I apparently overwrote /etc/group so my user account lost its group assignments. The errors thrown by mplayer were a little confusing because they mentioned "no such file", while in reports from other users with similar problems I could clearly see "permission denied". Only when running mplayer with "-ao oss" it correctly reported "permission denied" on /dev/dsp.

KDE must be simply assigning permissions when it detects a new device, perhaps it has something to do with ConsoleKit. It would also explain why you have to actually be in Konsole when modprobing because it wouldn't work in a text console even with KDE running in the background.

Anyway, sorry for bothering. Have a nice day, or good night, depending on your timezone

Last edited by swiergot (2009-11-22 08:38:27)