Re: [linux-audio-user] ALSA and usb-audio

New Message Reply About this list Date view Thread view Subject view Author view Other groups

Subject: Re: [linux-audio-user] ALSA and usb-audio
From: Fernando Pablo Lopez-Lezcano (nando_AT_ccrma.Stanford.EDU)
Date: Sun Aug 04 2002 - 23:13:48 EEST


> > No it sounds like you have done everything correctly so I don't know
> > what could be the cause.

Just a guess, I think the computer might not be fast enough to extract
from the cd and send to the usb interface. One way to find out would be to
try to rip the cd with a standalone program (cdparanoia for example?) and
see how fast it can rip. If it is close to real-time that could be the
problem (or you could try grip, I think it shows how fast the rip is
going).

> Another thought: since, at this point, playing CDs is the one thing that
> isn't yet working through the USB audio unit, would it be possible to
> set things so that the CDs play through the laptop's built-in headphone
> port (to which the CD drive is apparently hardwired). The sound isn't
> quite as good as through the USB, but sufficient for casual listening.
> According to the specs I checked, the internal sound chip is a
> Crystal Semiconductor CS4237B audio controller.
>
> I'm guessing that it should be simple, but I'm not clear on how to do
> it.

You need to change the /etc/modules.conf so that it can start both cards
(the internal and the usb card) and then use alsamixer to unmute and set
the level of the main and cd level controls of the internal chip.

This is an example you could use as template:

# --- ALSA configuration
alias char-major-116 snd
alias char-major-14 soundcore
alias snd-card-0 snd-ice1712
alias snd-card-1 snd-cmipci
# --- OSS compatibility
alias sound-slot-0 snd-card-0
alias sound-slot-1 snd-card-1
alias sound-service-0-0 snd-mixer-oss
alias sound-service-0-1 snd-seq-oss
alias sound-service-0-3 snd-pcm-oss
alias sound-service-0-8 snd-seq-oss
alias sound-service-0-12 snd-pcm-oss
alias sound-service-1-0 snd-mixer-oss
alias sound-service-1-1 snd-seq-oss
alias sound-service-1-3 snd-pcm-oss
alias sound-service-1-8 snd-seq-oss
alias sound-service-1-12 snd-pcm-oss
# --- Options
options snd snd_major=116 snd_cards_limit=2 snd_device_mode=0666
snd_device_gid=0 snd_device_uid=0
options snd-ice1712 snd_index=0 snd_id=OmniIO
options snd-cmipci snd_index=1 snd_id=CM8738
# --- Keep modules from being autocleaned
add options -k snd-card-0
add options -k snd-card-1
# --- ALSA configuration END

Just replace the proper module names for both cards, do a "depmod -a" and
restart the alsa driver "/etc/rc.d/init.d/alsasound restart".

"alsamixer -c 1" will access the second card. After everything is running
again (or not :-) you can save the settings for both mixers (don't know if
the usb cards has one) by saying "/usr/sbin/alsactl store".

From the alsa soundcard matrix it seems you should try "snd-cs4236" for
the internal card driver.

-- Fernando


New Message Reply About this list Date view Thread view Subject view Author view Other groups

This archive was generated by hypermail 2b28 : Sun Aug 04 2002 - 23:10:51 EEST