Perhaps; 1. Boot with knoppix 2. record lsmod output 3. Boot back into gentoo, go to kernel setup and select any missing modules, them make modules_install, and modprobe the modules (no need to reboot) 4. Try alsa again to see if anything has turned up?
FWIW on my laptop; sphinx adam # lspci | grep -i audio 00:1b.0 Audio device: Intel Corporation 82801I (ICH9 Family) HD Audio Controller (rev 03) 01:00.1 Audio device: ATI Technologies Inc RV635 Audio device [Radeon HD 3600 Series] sphinx adam # lsmod | grep snd snd_pcm_oss 36995 0 snd_mixer_oss 14411 1 snd_pcm_oss snd_seq_oss 26559 0 snd_seq_midi_event 5180 1 snd_seq_oss snd_seq 47389 4 snd_seq_oss,snd_seq_midi_event snd_seq_device 4949 2 snd_seq_oss,snd_seq snd_hda_codec_atihdmi 2515 1 snd_hda_codec_idt 49279 1 snd_hda_intel 19482 0 snd_hda_codec 61897 3 snd_hda_codec_atihdmi,snd_hda_codec_idt,snd_hda_intel snd_pcm 69399 3 snd_pcm_oss,snd_hda_intel,snd_hda_codec snd_timer 17735 2 snd_seq,snd_pcm snd 49836 10 snd_pcm_oss,snd_mixer_oss,snd_seq_oss,snd_seq,snd_seq_device,snd_hda_codec_idt,snd_hda_intel,snd_hda_codec,snd_pcm,snd_timer snd_page_alloc 6705 2 snd_hda_intel,snd_pcm
