Mine

#This asoundrc is for snd_intel8x0 based cards. 
#It will allow the following:
#
#	upmix stereo files to 5.1 speakers.
#	playback real 5.1 sounds, on 5.1 speakers,
#	allow the playback of both stere(oupmixed) and surround(5.1) sources at the same time.
#
#
#Please try the following commands, to make sure everything is working as it should.
#
#	To test stereo upmix : speaker-test -c2 -Ddefault -twav
#	To test surround(5.1): speaker-test -c6 -Dplug:dmix6 -twav
#
#
#It may not work out of the box for all cards. If it doesnt work for you, read the comments throughout the file.
#If it still doesnt work with your setup, please speak to me (wishie) in #alsa on irc.freenode.net

# 6 channel dmix - output whatever audio, to all 6 speakers
pcm.dmix6 {
     type dmix
        ipc_key 1024
        ipc_key_add_uid false
        ipc_perm 0660
        slave {
                pcm "hw:0,0"
                rate 48000
                channels 6
                period_time 0
                period_size 1024
                buffer_time 0
                buffer_size 4096
        }

# Some cards, like the "nforce" variants require the following to be uncommented. It routes the audio to the correct speakers.
	bindings {
		0 0
		1 1
		2 4
		3 5
		4 2
		5 3
	}

     }

# upmixing - duplicate stereo data to all 6 channels
pcm.ch51dup {
        type route
        slave.pcm dmix6
        slave.channels 6
        ttable.0.0 1
        ttable.1.1 1
        ttable.0.2 1
        ttable.1.3 1
        ttable.0.4 0.5
        ttable.1.4 0.5
        ttable.0.5 0.5
        ttable.1.5 0.5
   }


# 'full-duplex' device for use with aoss
pcm.duplex {
     type asym
     playback.pcm "ch51dup"
     capture.pcm "hw:0"
}

# change default device:
pcm.!default {
     type softvol 
     slave.pcm "duplex"
	control {
		name "Software Master"
		card 0 
	}
}

# for aoss
pcm.dsp "duplex"
pcm.dsp0 "duplex"
pcm.dsp1 "duplex"