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Old 09-21-2004, 11:55 AM   #1
Dargason
LQ Newbie
 
Registered: Jul 2004
Location: Leuven, Belgium
Distribution: Mandrake 10, LFS 5.1.1, Debian
Posts: 29

Rep: Reputation: 15
no sound from /dev/dsp


Greetings!

I'm trying to set up MythTV on my system, and I'm running into some problems getting the sound to work. I'm running Debian "Sarge" and I've installed ALSA version 1.0.5. I've been working with several versions of MythTV, including 0.15, 0.16, and now I'm running a CVS snapshot from a couple of days ago. My sound card is an old SoundBlaster Live Value card. My TV capture card is a Hauppauge WinTV Go2 card that uses the cx88 driver. I've patched the "sarge" kernel to include the latest version (0.0.4) of this driver.

When I run XawTV, I get video and sound to work fine. The MythTV troubleshooting docs say that XawTV isn't a good test because it patches the analog in to the analog out and bypasses the DSP. Instead, it suggests to start up XawTV, mute it, then use "aplay /dev/dsp" to check the "digitized" audio. Unfortunately, when I do this, I get:

Playing raw data '/dev/dsp' : Unsigned 8 bit, Rate 8000 Hz, Mono
underrun!!! (at least 10.664 ms long)
underrun!!! (at least 11.706 ms long)
underrun!!! (at least 11.763 ms long)

I think this means that /dev/dsp isn't getting the audio... I've made sure to use alsamixer to set the capture settings, line in, master volume, etc the way they said on the troubleshooting guide, although I admit I'm not 100% sure I got it right.

The security modes for /dev/dsp* and /dev/mixer* are all 777, so access shouldn't be a problem here. Also, when I do a "fuser -v /dev/dsp" I get nothing which I assume means that nobody has tied up the device.

What am I missing here? I'm so close...

Thanks,
Mike
 
Old 09-21-2004, 12:09 PM   #2
Dargason
LQ Newbie
 
Registered: Jul 2004
Location: Leuven, Belgium
Distribution: Mandrake 10, LFS 5.1.1, Debian
Posts: 29

Original Poster
Rep: Reputation: 15
Some more info:

lspci:

0000:00:00.0 Host bridge: nVidia Corporation nForce2 AGP (different version?) (rev a2)
0000:00:00.1 RAM memory: nVidia Corporation nForce2 Memory Controller 1 (rev a2)
0000:00:00.2 RAM memory: nVidia Corporation nForce2 Memory Controller 4 (rev a2)
0000:00:00.3 RAM memory: nVidia Corporation nForce2 Memory Controller 3 (rev a2)
0000:00:00.4 RAM memory: nVidia Corporation nForce2 Memory Controller 2 (rev a2)
0000:00:00.5 RAM memory: nVidia Corporation nForce2 Memory Controller 5 (rev a2)
0000:00:01.0 ISA bridge: nVidia Corporation nForce2 ISA Bridge (rev a3)
0000:00:01.1 SMBus: nVidia Corporation nForce2 SMBus (MCP) (rev a2)
0000:00:02.0 USB Controller: nVidia Corporation nForce2 USB Controller (rev a3)
0000:00:02.1 USB Controller: nVidia Corporation nForce2 USB Controller (rev a3)
0000:00:02.2 USB Controller: nVidia Corporation nForce2 USB Controller (rev a3)
0000:00:04.0 Ethernet controller: nVidia Corporation nForce2 Ethernet Controller (rev a1)
0000:00:06.0 Multimedia audio controller: nVidia Corporation nForce2 AC97 Audio Controler (MCP) (rev a1)
0000:00:08.0 PCI bridge: nVidia Corporation nForce2 External PCI Bridge (rev a3)
0000:00:09.0 IDE interface: nVidia Corporation nForce2 IDE (rev a2)
0000:00:1e.0 PCI bridge: nVidia Corporation nForce2 AGP (rev a2)
0000:01:08.0 Multimedia audio controller: Creative Labs SB Live! EMU10k1 (rev 08)
0000:01:08.1 Input device controller: Creative Labs SB Live! MIDI/Game Port (rev 08)
0000:01:09.0 Multimedia video controller: Conexant Winfast TV2000 XP (rev 03)
0000:01:09.1 Multimedia controller: Conexant: Unknown device 8811 (rev 03)
0000:02:00.0 VGA compatible controller: ATI Technologies Inc Radeon R300 ND [Radeon 9700 Pro]
0000:02:00.1 Display controller: ATI Technologies Inc Radeon R300 [Radeon 9700 Pro] (Secondary)

lsmod:
Module Size Used by
snd_pcm_oss 48424 0
snd_mixer_oss 17152 1 snd_pcm_oss
nls_cp437 6016 1
ntfs 83404 1
vfat 13440 0
fat 41664 1 vfat
floppy 54100 0
af_packet 20872 2
tuner 18448 0
cx8800 44060 1
cx88xx 20356 1 cx8800
video_buf 20484 2 cx8800,cx88xx
i2c_algo_bit 8968 1 cx8800
v4l1_compat 13444 1 cx8800
v4l2_common 6400 1 cx8800
btcx_risc 4744 2 cx8800,cx88xx
videodev 9856 2 cx8800
i2c_core 22292 4 tuner,cx8800,cx88xx,i2c_algo_bit
emu10k1_gp 3840 0
snd_emu10k1 80776 1
snd_rawmidi 23488 1 snd_emu10k1
snd_pcm 86052 2 snd_pcm_oss,snd_emu10k1
snd_timer 23300 1 snd_pcm
snd_seq_device 7944 2 snd_emu10k1,snd_rawmidi
snd_ac97_codec 59652 1 snd_emu10k1
snd_page_alloc 11144 2 snd_emu10k1,snd_pcm
snd_util_mem 4608 1 snd_emu10k1
snd_hwdep 9120 1 snd_emu10k1
snd 50148 12 snd_pcm_oss,snd_mixer_oss,snd_emu10k1,snd_rawmidi,snd_pcm,snd_timer,snd_seq_device,snd_ac97_codec,sn d_util_mem,snd_hwdep
soundcore 9824 1 snd
ohci_hcd 19460 0
nvidia_agp 7580 1
agpgart 31272 1 nvidia_agp
evdev 9088 0
ehci_hcd 27908 0
usbcore 101088 4 ohci_hcd,ehci_hcd
forcedeth 14336 0
ide_cd 38788 0
cdrom 35616 1 ide_cd
genrtc 9480 0
ide_generic 1664 0
amd74xx 13980 1
unix 26032 446
 
Old 09-22-2004, 02:26 AM   #3
Dargason
LQ Newbie
 
Registered: Jul 2004
Location: Leuven, Belgium
Distribution: Mandrake 10, LFS 5.1.1, Debian
Posts: 29

Original Poster
Rep: Reputation: 15
Does anyone have any suggestions on what to try next? Is there any way for me to tell what /dev/dsp is connected to? Should I just reinstall everything?

Any ideas are welcome!

Thanks,
Mike
 
Old 09-23-2004, 02:58 AM   #4
Dargason
LQ Newbie
 
Registered: Jul 2004
Location: Leuven, Belgium
Distribution: Mandrake 10, LFS 5.1.1, Debian
Posts: 29

Original Poster
Rep: Reputation: 15
Ok, just in case anyone is following this -- I'm sure someone is struggling with something like this -- here is an update.

I re-installed everything, again with the 2.6.7 kernel. This time I tried using alsa before I recompiled the kernel:

apt-get install alsa

which loaded alsa-base and alsa-utils, since the alsa-driver stuff is included in the kernel. Then I did alsaconf to configure things. This resulted in a mess: alsamixer couldn't find any mixers, and trying to aplay /dev/dsp resulted in "no such device" sort of errors. But sound worked, generally speaking.

So I recompiled the kernel, removing a whole bunch of stuff including the support for OSS. I didn't apply any patches to the source. I rebooted and installed alsa again. At this point I was back to the behavior I had before -- everything seemed to work fine, except when I try to work through /dev/dsp. Doing an "aplay /dev/dsp" results in buffer underruns, and trying a "cat <file> > /dev/dsp" results in no sound...

As I lay in bed last night waiting for sleep to come, I recalled that this motherboard has an on-board sound card. I normally have this disabled in BIOS, but I had an issue a few weeks ago that caused my CMOS settings to be reset. So this morning I went into the BIOS and disabled the onboard sound and re-ran alsaconf. Progress! Now I get static when I do "cat kernel-image > /dev/dsp" so at least I believe /dev/dsp (actually /dev/dsp0) is connected to the right place. But I still get buffer underruns when I try to do "aplay /dev/dsp".

So maybe I still don't have my mixer settings setup right... I'm tempted to do another complete re-install, this time with the onboard sound disabled, and see if that makes any difference.

Any other suggestions? These re-installs seem like an awefully big hammer to be using to troubleshoot this... but I don't know another way to be certain that alsa is completely "reset". Ah well, I'm learning quite a bit.
 
Old 10-22-2004, 11:53 PM   #5
finley
LQ Newbie
 
Registered: Oct 2004
Distribution: debian unstable
Posts: 3

Rep: Reputation: 1
Thanks! Resolution?

First, it's nice to finally find evidence that someone else is having the _exact_ same issue (same capture card, same audio card, same code builds -- including post 0.16 cvs). But I haven't resolved mine yet. Did you find a solution?

Cheers, -Finley
 
Old 10-24-2004, 03:30 AM   #6
Dargason
LQ Newbie
 
Registered: Jul 2004
Location: Leuven, Belgium
Distribution: Mandrake 10, LFS 5.1.1, Debian
Posts: 29

Original Poster
Rep: Reputation: 15
Well, I actually got pretty close. I have both sound systems (onboard and PCI) working, including /dev/dsp. XawTV worked fine. MythTV worked -- except for no audio!

So I tried upgrading to the CVS version of the cx88 drivers. After that, I can no longer change channels... So I'm taking a break from this project. Perhaps in the meantime some of these bugs will get fixed.

I have some notes I made on how to install a working system - or at least working as well as I could get it. If you want, I can post them. Let me know.

Mike
 
Old 10-25-2004, 10:28 PM   #7
finley
LQ Newbie
 
Registered: Oct 2004
Distribution: debian unstable
Posts: 3

Rep: Reputation: 1
Still trying...

Thanks for the reply, Mike.

I'm going to give it a try with an old 1998 model Hauppauge WinTV card to see if that works. If so, I think I'll be returning the Conexant Winfast TV2000 XP card. I'll keep posting my progress here.

Cheers, -Brian
 
Old 11-02-2004, 06:44 PM   #8
android1654
Member
 
Registered: Jan 2003
Location: Baltimore
Distribution: Slackware,peanut linux
Posts: 30

Rep: Reputation: 15
I am having the exact some problem/error messages you defined in your original post with a slightly different software/hardware:

slackware 10, kde, soundblaster audigy, alsa.

alsa works fine for me in all situations, but when i try to aplay /dev/dsp or /dev/(any sound channel: dsp0.. adsp..etc.) i get the errors.


does anyone have any suggestions for this. im so close to getting mythtv working!
 
Old 11-04-2004, 07:14 AM   #9
Dargason
LQ Newbie
 
Registered: Jul 2004
Location: Leuven, Belgium
Distribution: Mandrake 10, LFS 5.1.1, Debian
Posts: 29

Original Poster
Rep: Reputation: 15
I don't have my notes with me (I'm at work) but try the following:

Make sure that you have some input to the card -- maybe you can unplug the "line-in" from the sound card and run it directly to a speaker.
Once you have verified that there is audio going into the "line-in", try running "aplay /dev/dsp"... but make sure you let it run for at least a second or two. I noticed at some point that even when things were working "right" I tended to get those buffer underrun errors for a second or two, then they would go away and I could hear the sound (assuming the mixer settings were right).

I'm afraid my memory is a bit fuzzy as I haven't really worked on this for several weeks, but I hope this helps. If not, I'll be travelling for the next couple of weeks but perhaps I can help out when I get back.

Mike
 
Old 11-04-2004, 08:33 AM   #10
theYinYeti
Senior Member
 
Registered: Jul 2004
Location: France
Distribution: Arch Linux
Posts: 1,897

Rep: Reputation: 61
Hi,

It seems I have the same problem, with kernel-2.6.8.1, ALSA 1.0.5a drivers+utils, onboard vt8235 audio (via82xx module), and a saa7134-based PCTV Stereo.

In Xawdecode, sound is OK for 1 or 2 seconds, then there's only noise (actually over the barely audible real sound). If I try to mute xawdecode, and run aplay /dev/dsp, I get exactly the same errors:
Code:
Playing raw data '/dev/dsp' : Unsigned 8 bit, Rate 8000 Hz, Mono
underrun!!! (at least 10.664 ms long)
Any news?

Yves.
 
Old 11-05-2004, 02:08 AM   #11
simonnz
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Registered: Feb 2004
Location: Auckland, New Zealand
Distribution: Debian
Posts: 5

Rep: Reputation: 0
Me too!

I've been having the same problems too. I thought it must have been something I done, but it seems not. I have a saa7134 based card, alsa 1.0.5, kernel 2.6.8, running debian unstable. If I use ffmpeg, it records fine and plays back fine. When using mythtv, records with no sound
 
Old 11-05-2004, 09:39 AM   #12
theYinYeti
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Registered: Jul 2004
Location: France
Distribution: Arch Linux
Posts: 1,897

Rep: Reputation: 61
I've found that on Google:
http://www.spinics.net/lists/vfl/msg10674.html (and follow-ups)

I will see if it helps me... Maybe it will help you...
Be sure to share your results.

Yves.
 
Old 11-10-2004, 07:33 AM   #13
Warf
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Registered: Nov 2004
Distribution: Gentoo
Posts: 1

Rep: Reputation: 0
possible solution?

Just posting this here so that it might help others with a similar problem...

I had a situation almost identical to the original poster's, since it involved a cx88 TV card (MSI TV@nywhere) and a Sound Blaster Live card (SBLive Gamer). The audio-out on the TV@nywhere is connected to the Line-in jack on the SBLive. I too was getting the long list of underrun errors from "aplay /dev/dsp" and had no sound in any of my MythTV recordings, though I had the added symptom of having the TV sounds playing constantly (though quietly) in the background. Even more frustrating was that if I opened Myth, I could hear audio, but it was a few seconds out of sync with the video while watching Live TV. So it seemed I was close to getting the correct setup, but still hadn't quite managed it.

As far as I can tell, the surprisingly simple solution was this: I opened alsamixer from the command line, then I muted the "Line" control and set it as the capture source (highlight "Line", then press 'm', then space bar). Next, I set the "Capture" control as the recording destination (press space while on "Capture") and increased it to 100. Finally, I set the "AC97" control to zero, but (very important!) set the adjacent "AC97 Capture" control to 100. Without the AC97 Capture control set to some non-zero value, no sound came through in Myth whatsoever. Once that's done, you'll still have to play with the various levels in order to get a satisfactory sound out of your setup, but you should at least be out of the woods.

Now, I still get the underrun errors with "aplay /dev/dsp", but the TV sound comes through just fine, and my Myth recordings finally have sound too. I don't think this will fix every problem mentioned in this thread, but certainly the issues involving the SBLive series (or other AC97 compatible sound cards) should be resolved.

Btw, I'm running Gentoo, kernel 2.6.9, alsa 1.0.6, cx88 0.0.4, and MythTV 0.16. Getting Myth running on this box took a week of off-and-on hacking, but it's finally done.

Hope this helps someone out there!

Cheers,
Warf
 
Old 11-28-2004, 02:41 PM   #14
toddles13
LQ Newbie
 
Registered: Nov 2004
Location: Auckland NZ
Distribution: Gentoo
Posts: 4

Rep: Reputation: 1
I have had the same problem.
Try this it seems to work for me.
Start mythfrontend
Select live tv
Bring up console
Code:
v4lctl volume mute off
Turns on the sound for me.
Give it a try.

Now all i have to do it get the Channels setup correctly and the sound synced with the picture and i am away.

----- Edit ------
Oh yeah, I am using :
Asus TV card (saa7134)
Soundblaster live
Gentoo
2.6.9-gentoo-r4 kernel (gentoo-dev-sources)

Last edited by toddles13; 11-28-2004 at 02:44 PM.
 
Old 01-22-2005, 12:25 AM   #15
huzzaboo
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Registered: Jan 2005
Posts: 2

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v4ctl worked for me

I struggled with this for a couple weeks. The v4ctl command finally got audio playing for me in MythTV using a bt878 card patched through the AuxIn line of my sound card.

I added this command to my /etc/init.d/mythbackend startup script (my device is /dev/video1)
/usr/bin/v4lctl -c /dev/video1 volume mute off

For those also not getting satisfactory audio using the 'aplay /dev/video0' test, try this one instead:
# sox -w -r 44000 -t ossdsp /dev/dsp -t ossdsp /dev/dsp

-Larry
 
  


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