Implemented enableOSSEmulation option, which can be used to disable OSS emulation. On my home PC OSS emulation gives me a lot of annoying problems

svn path=/nixos/trunk/; revision=20351

modules/services/audio/alsa.nix

@@ -27,6 +27,13 @@ in
         merge = mergeEnableOption;
       };
       
+      enableOSSEmulation = mkOption {
+        default = true;
+	description = ''
+	  Whether to enable ALSA OSS emulation (with certain cards sound mixing may not work!).
+	'';
+      };
+
     };
     
   };
@@ -53,9 +60,14 @@ in
             mkdir -m 0755 -p $(dirname ${soundState})
 
             # Load some additional modules.
+	    
+	    ${optionalString config.sound.enableOSSEmulation
+	      ''
                 for mod in snd_pcm_oss; do
                   ${config.system.sbin.modprobe}/sbin/modprobe $mod || true
                 done
+	      ''
+	    }
 
             # Restore the sound state.
             ${alsaUtils}/sbin/alsactl -f ${soundState} restore