[mythtv-users] ALSA and SPDIF Out For nForce2 Motherboards

[Scott Elliott]

On Tue, 2004-04-06 at 23:53, Mike Denver wrote:
> When I select /dev/adsp0 then start tv my computer hangs. How can I
> determine if I have the OSS emulation modules installed? This is kinda
> frustrating cause it seems that everyone says do this and it should work,
> and it's a different solution every time. Are they all pieces of one big
> puzzle? Or are they all just different was of getting to the same solution?
> 

# lsmod | grep oss
snd_pcm_oss            49540  2
snd_mixer_oss          17856  1 snd_pcm_oss
snd_pcm                85760  3 snd_pcm_oss,snd_bt87x,snd_intel8x0
snd                    47108  10
snd_pcm_oss,snd_mixer_oss,snd_bt87x,snd_intel8x0,snd_ac97_codec,snd_pcm,snd_timer,snd_mpu401_uart,snd_rawmidi,snd_seq_device

I'm using a Nforce2 board, and two WinTV-dbx cards, so that's why
snd_bt87x is loaded.  Also, since I'm using devfs, I have the following
devices in /dev/sound:

crw-rw----    1 root     audio     14,  12 Dec 31  1969 adsp
crw-rw----    1 root     audio     14,  28 Dec 31  1969 adsp1
crw-rw----    1 root     audio     14,  44 Dec 31  1969 adsp2
crw-rw----    1 root     audio     14,   4 Dec 31  1969 audio
crw-rw----    1 root     audio     14,  20 Dec 31  1969 audio1
crw-rw----    1 root     audio     14,  36 Dec 31  1969 audio2
crw-rw----    1 root     audio     14,   3 Dec 31  1969 dsp
crw-rw----    1 root     audio     14,  19 Dec 31  1969 dsp1
crw-rw----    1 root     audio     14,  35 Dec 31  1969 dsp2
crw-rw----    1 root     audio     14,   0 Dec 31  1969 mixer
crw-rw----    1 root     audio     14,  16 Dec 31  1969 mixer1
crw-rw----    1 root     audio     14,  32 Dec 31  1969 mixer2


Module options for ALSA are:

options snd cards_limit=3
options snd-intel8x0 ac97_clock=48000
options snd-pcm-oss adsp_map=2
options snd-bt87x enable=1,1 digital_rate=32000,32000

The adsp_map=2 is there because some time ago, the SPDIF device changed
from 1 to 2, and 1 became the microphone input.  You can see this by
using "aplay -l" and "arecord -l"

# aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: nForce [NVidia nForce], device 0: Intel ICH [NVidia nForce]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: nForce [NVidia nForce], device 2: Intel ICH - IEC958 [NVidia
nForce - IEC958]
  Subdevices: 0/1
  Subdevice #0: subdevice #0
# arecord -l
**** List of CAPTURE Hardware Devices ****
card 0: nForce [NVidia nForce], device 0: Intel ICH [NVidia nForce]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: nForce [NVidia nForce], device 1: Intel ICH - MIC ADC [NVidia
nForce - MIC ADC]
  Subdevices: 1/1
  Subdevice #0: subdevice #1

One other thing:  I had to modify /usr/share/alsa/cards/NFORCE.conf for
the NFORCE.pcm.iec958.0 entry.  The element should be:

        slave.pcm {
                type hw
                card $CARD
                device 2
        }

"device" was "1".  But this may have been corrected (I'm running ALSA
1.0.1)

-- 
Scott Elliott <selliott at insight.rr.com>