Question about linux sound... 1023

On Saturday 08 April 2006 01:55, Trixx stood up and spoke the following words to the mbuttes incomp.os.linux.misc...:

Sound coming from multiple sources at the same time - either in realtime or with a slight delay - is calledduplexmode. Full duplex means that your soundcard can actually concurrently process multiple sound sources - e.g. mouseclicks and anmp3playback.

In order to have full duplex, there are two conditions. First of all, your soundcard needs to support it - I can't vouch for the AC97 chipset in this regard, but I'd be surprised if it didn't - and secondly, the driver used for that soundcard (or chipset) needs to have full duplex capability compiled in. Chances are that the chipset supports it but that the binary driver doesn't - the source code may actually support it but it may have been disabled at compile time.

Debian is a nice and stable distribution, but not quite an up-to-date one in terms of software packages - at least not if you go for what Debian marks as the "stable" branch. The use of a 2.4.27 kernel in your distribution shows this - the current stablevanillakernel is at 2.6.16.2 as of yesterday April 7th (with 2.6.17 already in RC1 stage) and most other distributions already do feature a stock 2.6-generation kernel.

Important in this respect is that the 2.4-generation of kernels mostly used the OSS (Open Sound System) drivers, while the default in Linux 2.6 is to use ALSA (Advanced Linux Sound Architecture) for driving the soundcard. ALSA does have OSS emulation, but you cannot use both native ALSA and native OSS concurrently for the same soundcard.

I would advise testing ALSA, preferably with a 2.6 kernel. It's highly possible that running a 2.6 kernel in a system compiled for 2.4 may break other things, though. For instance, on my system it broke IP forwarding and masquerading. That's why it's also important to note that ALSA *is* also available in the 2.4-generation of kernels.

If the sound issue is really important to you and provided that you succeed in achieving full duplex functionality with a 2.6 kernel and ALSA drivers, then I would advise you to switch to a different distribution, or perhaps one of the "marked less stable" Debian branches - or maybe even Ubuntu or Kubuntu, which are Debian-based - in order to avoid conflicts between a 2.4-compiled distribution and a 2.6-generation kernel.

Hope this was helpful... ;-)

-- With kind regards,

*Aragorn* (Registered GNU-Linux user #223157)