[gentoo-user] Sound issue - can't use /dev/dsp

[gentoo-user] Sound issue - can't use /dev/dsp

[Andrew MacKenzie]

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My MythTV Gentoo box has recently started having issues recording sound.
The TV tuner re-plays audio through the "mic" interface on my soundcard.
It has worked for months, but now MythTV can't read anything from /dev/dsp.

Any device that uses ALSA directly seems to work fine (like TVTime which
plays TV with audio just fine) - only those that rely on /dev/dsp seem to
have trouble.  My simple test shows this:

# cat /dev/dsp > /dev/null
cat: /dev/dsp: Input/output error

This was run as root.  Perms are fine:

crw-rw---- 1 root audio 14, 3 2008-10-03 08:56 /dev/dsp

Myth user is in audio group (always has been).  

Has something changed in ALSA that I didn't catch?  I don't see anything in
my logs or dmesg that shows a problem.  My /etc/asound.conf is as follows:
pcm.nforce-hw {
        type hw
        card 0
}
pcm.!default {
        type plug
        slave.pcm "nforce"
}
pcm.nforce {
        type dmix
        ipc_key 1234
        ipc_perm 0660
        slave {
                pcm "hw:0,0"
                period_time 0
                period_size 1024
                buffer_size 4096
                #rate 44100
                rate 48000
        }
}
ctl.nforce-hw {
        type hw
        card 0
}


I have tried without this asound.conf and see the same issue.

-- 
// Andrew MacKenzie  |  http://www.edespot.com
// GPG public key: http://www.edespot.com/~amackenz/public.key
// I've touch'd the highest point of all my greatness;
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// Like a bright exhalation in the evening
// And no man see me more.
//                 -- Shakespeare

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Re: [gentoo-user] Sound issue - can't use /dev/dsp

[Andrey Vul]

On Thu, Oct 30, 2008 at 12:41 PM, Andrew MacKenzie <amackenz@edespot.com> wrote:
> My MythTV Gentoo box has recently started having issues recording sound.
> The TV tuner re-plays audio through the "mic" interface on my soundcard.
> It has worked for months, but now MythTV can't read anything from /dev/dsp.
>
> Any device that uses ALSA directly seems to work fine (like TVTime which
> plays TV with audio just fine) - only those that rely on /dev/dsp seem to
> have trouble.  My simple test shows this:
>
> # cat /dev/dsp > /dev/null
> cat: /dev/dsp: Input/output error
>
> This was run as root.  Perms are fine:
>
> crw-rw---- 1 root audio 14, 3 2008-10-03 08:56 /dev/dsp
>
> Myth user is in audio group (always has been).
>
> Has something changed in ALSA that I didn't catch?  I don't see anything in
> my logs or dmesg that shows a problem.  My /etc/asound.conf is as follows:
> pcm.nforce-hw {
>        type hw
>        card 0
> }
> pcm.!default {
>        type plug
>        slave.pcm "nforce"
> }
> pcm.nforce {
>        type dmix
>        ipc_key 1234
>        ipc_perm 0660
>        slave {
>                pcm "hw:0,0"
>                period_time 0
>                period_size 1024
>                buffer_size 4096
>                #rate 44100
>                rate 48000
>        }
> }
> ctl.nforce-hw {
>        type hw
>        card 0
> }
>
>
> I have tried without this asound.conf and see the same issue.
Try using alsaconf as root.


-- 
Andrey Vul

A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
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Re: [gentoo-user] Sound issue - can't use /dev/dsp

[Andrew MacKenzie]

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+++ Andrey Vul [gentoo-user] [Thu, Oct 30, 2008 at 01:01:39PM -0400]:
> On Thu, Oct 30, 2008 at 12:41 PM, Andrew MacKenzie <amackenz@edespot.com> wrote:
> > I have tried without this asound.conf and see the same issue.
> Try using alsaconf as root.
alsaconf ran fine.  I stopped 'alsa' (and noted that all snd modules were
unloaded), ran alsaconf, and noted that modules were now loaded.

Still can't get sound via /dev/dsp.  It's my understanding that snd_pcm_oss
should be the one that handles /dev/dsp.

The following 'snd' related modules are loaded:
# lsmod |grep snd
snd_pcm_oss            41824  0
snd_mixer_oss          16640  1 snd_pcm_oss
snd_intel8x0           34024  0
snd_ac97_codec        117784  1 snd_intel8x0
snd_pcm                87256  3 snd_pcm_oss,snd_intel8x0,snd_ac97_codec
snd_page_alloc          9424  2 snd_intel8x0,snd_pcm
ac97_bus                2240  1 snd_ac97_codec

My kernel is 2.6.26-gentoo-r1.  But I tried another couple from 2.6.24 and
didn't have success there either.  I wonder whether it's a user-land lib
issue?

Installed:
alsa-lib 1.0.16
alsa-oss 1.0.15
alsa-tools 1.0.16
alsa-utils 1.0.16

-- 
// Andrew MacKenzie  |  http://www.edespot.com
// GPG public key: http://www.edespot.com/~amackenz/public.key
// There is an old time toast which is golden for its beauty.
// "When you ascend the hill of prosperity may you not meet a friend."
//                 -- Mark Twain

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