Obtendo áudio aberto em nvidia hdmi

Question

Eu quero obter programas que usam openal para enviar som através da saída HDMI da minha placa nvidia usando bibliotecas alsa diretamente. Aqui está minha configuração:

root@localhost /root % cat /proc/asound/cards               
 0 [PCH            ]: HDA-Intel - HDA Intel PCH
                      HDA Intel PCH at 0xef420000 irq 136
 1 [NVidia         ]: HDA-Intel - HDA NVidia
                      HDA NVidia at 0xef080000 irq 17
root@localhost /root %

Parece não haver um módulo de kernel carregado para a placa de som Nvidia (no Windows® há um driver de placa de som específico) . Se necessário, não tenho idéia do módulo do kernel para carregar.

root@localhost /root % lsmod | grep snd    
snd_hda_intel          36864  0
snd_hda_codec_realtek    90112  1
snd_hda_codec_generic    73728  1 snd_hda_codec_realtek
snd_hda_codec_hdmi     49152  2
snd_hda_codec         135168  4 snd_hda_intel,snd_hda_codec_hdmi,snd_hda_codec_generic,snd_hda_codec_realtek
snd_hda_core           81920  5 snd_hda_intel,snd_hda_codec,snd_hda_codec_hdmi,snd_hda_codec_generic,snd_hda_codec_realtek
snd_hwdep              16384  1 snd_hda_codec
snd_pcm               114688  4 snd_hda_intel,snd_hda_codec,snd_hda_core,snd_hda_codec_hdmi
snd_timer              32768  1 snd_pcm
snd                    86016  8 snd_hda_intel,snd_hwdep,snd_hda_codec,snd_timer,snd_hda_codec_hdmi,snd_hda_codec_generic,snd_hda_codec_realtek,snd_pcm
soundcore              16384  1 snd
root@localhost /root %

Então eu desmutei entradas spdif em alsamixer: mas o som ainda está sendo enviado para os alto-falantes do meu PC em vez do HDMI (talvez seja normal, já que não há cabo de entrada SPDIF na minha placa gráfica).

Eu li sobre .asoundrc , mas não tenho ideia de qual dispositivo selecionar (o áudio hdmi) :

root@localhost /root % aplay -L
null
    Discard all samples (playback) or generate zero samples (capture)
default:CARD=PCH
    HDA Intel PCH, ALC887-VD Analog
    Default Audio Device
sysdefault:CARD=PCH
    HDA Intel PCH, ALC887-VD Analog
    Default Audio Device
front:CARD=PCH,DEV=0
    HDA Intel PCH, ALC887-VD Analog
    Front speakers
surround21:CARD=PCH,DEV=0
    HDA Intel PCH, ALC887-VD Analog
    2.1 Surround output to Front and Subwoofer speakers
surround40:CARD=PCH,DEV=0
    HDA Intel PCH, ALC887-VD Analog
    4.0 Surround output to Front and Rear speakers
surround41:CARD=PCH,DEV=0
    HDA Intel PCH, ALC887-VD Analog
    4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=PCH,DEV=0
    HDA Intel PCH, ALC887-VD Analog
    5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=PCH,DEV=0
    HDA Intel PCH, ALC887-VD Analog
    5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=PCH,DEV=0
    HDA Intel PCH, ALC887-VD Analog
    7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
iec958:CARD=PCH,DEV=0
    HDA Intel PCH, ALC887-VD Digital
    IEC958 (S/PDIF) Digital Audio Output
hdmi:CARD=PCH,DEV=0
    HDA Intel PCH, HDMI 0
    HDMI Audio Output
hdmi:CARD=PCH,DEV=1
    HDA Intel PCH, HDMI 1
    HDMI Audio Output
hdmi:CARD=PCH,DEV=2
    HDA Intel PCH, HDMI 2
    HDMI Audio Output
dmix:CARD=PCH,DEV=0
    HDA Intel PCH, ALC887-VD Analog
    Direct sample mixing device
dmix:CARD=PCH,DEV=1
    HDA Intel PCH, ALC887-VD Digital
    Direct sample mixing device
dmix:CARD=PCH,DEV=3
    HDA Intel PCH, HDMI 0
    Direct sample mixing device
dmix:CARD=PCH,DEV=7
    HDA Intel PCH, HDMI 1
    Direct sample mixing device
dmix:CARD=PCH,DEV=8
    HDA Intel PCH, HDMI 2
    Direct sample mixing device
dsnoop:CARD=PCH,DEV=0
    HDA Intel PCH, ALC887-VD Analog
    Direct sample snooping device
dsnoop:CARD=PCH,DEV=1
    HDA Intel PCH, ALC887-VD Digital
    Direct sample snooping device
dsnoop:CARD=PCH,DEV=3
    HDA Intel PCH, HDMI 0
    Direct sample snooping device
dsnoop:CARD=PCH,DEV=7
    HDA Intel PCH, HDMI 1
    Direct sample snooping device
dsnoop:CARD=PCH,DEV=8
    HDA Intel PCH, HDMI 2
    Direct sample snooping device
hw:CARD=PCH,DEV=0
    HDA Intel PCH, ALC887-VD Analog
    Direct hardware device without any conversions
hw:CARD=PCH,DEV=1
    HDA Intel PCH, ALC887-VD Digital
    Direct hardware device without any conversions
hw:CARD=PCH,DEV=3
    HDA Intel PCH, HDMI 0
    Direct hardware device without any conversions
hw:CARD=PCH,DEV=7
    HDA Intel PCH, HDMI 1
    Direct hardware device without any conversions
hw:CARD=PCH,DEV=8
    HDA Intel PCH, HDMI 2
    Direct hardware device without any conversions
plughw:CARD=PCH,DEV=0
    HDA Intel PCH, ALC887-VD Analog
    Hardware device with all software conversions
plughw:CARD=PCH,DEV=1
    HDA Intel PCH, ALC887-VD Digital
    Hardware device with all software conversions
plughw:CARD=PCH,DEV=3
    HDA Intel PCH, HDMI 0
    Hardware device with all software conversions
plughw:CARD=PCH,DEV=7
    HDA Intel PCH, HDMI 1
    Hardware device with all software conversions
plughw:CARD=PCH,DEV=8
    HDA Intel PCH, HDMI 2
    Hardware device with all software conversions
hdmi:CARD=NVidia,DEV=0
    HDA NVidia, HDMI 0
    HDMI Audio Output
hdmi:CARD=NVidia,DEV=1
    HDA NVidia, HDMI 1
    HDMI Audio Output
hdmi:CARD=NVidia,DEV=2
    HDA NVidia, HDMI 2
    HDMI Audio Output
hdmi:CARD=NVidia,DEV=3
    HDA NVidia, HDMI 3
    HDMI Audio Output
dmix:CARD=NVidia,DEV=3
    HDA NVidia, HDMI 0
    Direct sample mixing device
dmix:CARD=NVidia,DEV=7
    HDA NVidia, HDMI 1
    Direct sample mixing device
dmix:CARD=NVidia,DEV=8
    HDA NVidia, HDMI 2
    Direct sample mixing device
dmix:CARD=NVidia,DEV=9
    HDA NVidia, HDMI 3
    Direct sample mixing device
dsnoop:CARD=NVidia,DEV=3
    HDA NVidia, HDMI 0
    Direct sample snooping device
dsnoop:CARD=NVidia,DEV=7
    HDA NVidia, HDMI 1
    Direct sample snooping device
dsnoop:CARD=NVidia,DEV=8
    HDA NVidia, HDMI 2
    Direct sample snooping device
dsnoop:CARD=NVidia,DEV=9
    HDA NVidia, HDMI 3
    Direct sample snooping device
hw:CARD=NVidia,DEV=3
    HDA NVidia, HDMI 0
    Direct hardware device without any conversions
hw:CARD=NVidia,DEV=7
    HDA NVidia, HDMI 1
    Direct hardware device without any conversions
hw:CARD=NVidia,DEV=8
    HDA NVidia, HDMI 2
    Direct hardware device without any conversions
hw:CARD=NVidia,DEV=9
    HDA NVidia, HDMI 3
    Direct hardware device without any conversions
plughw:CARD=NVidia,DEV=3
    HDA NVidia, HDMI 0
    Hardware device with all software conversions
plughw:CARD=NVidia,DEV=7
    HDA NVidia, HDMI 1
    Hardware device with all software conversions
plughw:CARD=NVidia,DEV=8
    HDA NVidia, HDMI 2
    Hardware device with all software conversions
plughw:CARD=NVidia,DEV=9
    HDA NVidia, HDMI 3
    Hardware device with all software conversions
root@localhost /root %

Além disso, nenhum dos dispositivos Nvidia desta lista funciona com aplay -D

root@localhost /root % aplay -Dhw:1 /usr/share/kde4/apps/kolf/sounds/blackhole.wav
aplay: main:788: No such file or directory

Procurando com o strace, parece que ele tenta abrir um arquivo de dispositivo não existente:

root@localhost /root % strace aplay -Dhw:1 /usr/share/kde4/apps/kolf/sounds/blackhole.wav 2>&1 | grep /dev/snd
open("/dev/snd/controlC1", O_RDONLY|O_CLOEXEC) = 3
open("/dev/snd/controlC1", O_RDWR|O_CLOEXEC) = 3
open("/dev/snd/pcmC1D0p", O_RDWR|O_NONBLOCK|O_CLOEXEC) = -1 ENOENT (No such file or directory)
root@localhost /root % 

O que parece normal, pois o dispositivo 1-1 não existe:

root@localhost /root % cat /proc/asound/devices
  1:        : sequencer
  2: [ 0]   : control
  3: [ 0- 0]: digital audio playback
  4: [ 0- 0]: digital audio capture
  5: [ 0- 1]: digital audio playback
  6: [ 0- 3]: digital audio playback
  7: [ 0- 7]: digital audio playback
  8: [ 0- 8]: digital audio playback
  9: [ 0- 0]: hardware dependent
 10: [ 0- 2]: hardware dependent
 11: [ 1]   : control
 12: [ 1- 3]: digital audio playback
 13: [ 1- 7]: digital audio playback
 14: [ 1- 8]: digital audio playback
 15: [ 1- 9]: digital audio playback
 16: [ 1- 0]: hardware dependent
 33:        : timer
root@localhost /root %

Além disso, descobri que a porta hdmi está desconectada, enquanto eu tenho o sinal de vídeo na televisão.