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alex6 Apprentice
Joined: 18 Jul 2011 Posts: 176
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Posted: Fri Apr 26, 2013 8:21 pm Post subject: Alsa underrun |
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I often get this message with several apps :
Quote: | ALSA lib pcm.c:7339:(snd_pcm_recover) underrun occurred |
lspci :
Quote: | 00:14.2 Audio device: Advanced Micro Devices [AMD] nee ATI SBx00 Azalia (Intel HDA) |
By the way, my soundcard is VIA VT1708S controry to what lspci shows...
Any idea how to fix this ? |
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PaulBredbury Watchman
Joined: 14 Jul 2005 Posts: 7310
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alex6 Apprentice
Joined: 18 Jul 2011 Posts: 176
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Posted: Sat Apr 27, 2013 10:54 am Post subject: |
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Quote: | In general, raise the app's priority, because audio is a real-time process. |
Thanks for your reply...Anyway, are you sure it's the good link ? This seems more related to file copy
Should I change my buffer size ?
Quote: | cat /proc/asound/card0/pcm0p/sub0/hw_params
access: MMAP_INTERLEAVED
format: S32_LE
subformat: STD
channels: 2
rate: 48000 (48000/1)
period_size: 1024
buffer_size: 8192
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Can it be a problem of frequency rate ? (most of the time default is 44.1, not 48) |
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PaulBredbury Watchman
Joined: 14 Jul 2005 Posts: 7310
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Posted: Sat Apr 27, 2013 12:33 pm Post subject: |
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alex6 wrote: | This seems more related to file copy |
No, it's for *both* nice and ionice.
Quote: | period_size: 1024
buffer_size: 8192
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Those are normally OK - I use those values. If getting under-runs, try doubling the buffer_size to 16384.
You should put more effort into understanding that link I gave you, and provide more detail, e.g. what apps? Also, check that your soundcard is configured correctly, e.g. model= and position_fix - google them. _________________ Improve your font rendering and ALSA sound |
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alex6 Apprentice
Joined: 18 Jul 2011 Posts: 176
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Posted: Sat Apr 27, 2013 1:54 pm Post subject: |
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Quote: | No, it's for *both* nice and ionice. |
Which one of those would be related to sound buffer ?
Quote: | If getting under-runs, try doubling the buffer_size to 16384. |
Do you mean with the .asounrc option ? Or is there another way to do that ?
A lot of apps, for example : Battle for Wesnoth or Wine (ok, wine has multiple sound issues so maybe it's normal)
Quote: |
provide more detail |
2 sound cards using the same driver (should be a cause of this problem maybe ?) :
Sound card #0 : VIA VT1708s driver snd_hda_intel
Sound card #1 : nvidia integrated soundcard on the graphic card (I don't need it, can't blacklist it by blacklisting the driver)
Here is how lspci detects it :
http://bpaste.net/show/94589/
Juste In case :
, lspci -vv
http://bpaste.net/show/94593/
aplay -l
http://bpaste.net/show/94595/
aplay -L
http://bpaste.net/show/94596/ |
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PaulBredbury Watchman
Joined: 14 Jul 2005 Posts: 7310
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Posted: Sat Apr 27, 2013 2:06 pm Post subject: |
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alex6 wrote: | Which one of those would be related to sound buffer ? |
Neither of them. nice is concerned with getting your app some CPU time when appropriate to stop the buffer from emptying.
Quote: | Do you mean with the .asoundrc option ? |
Yes, see buffer_size in the config in my sig, for how it's done.
Quote: | wine has multiple sound issues |
Sadly, this is true. E.g. Thief2 can crackle, but luckily Thief2 can use openal instead, which works much better. |
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alex6 Apprentice
Joined: 18 Jul 2011 Posts: 176
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Posted: Sat Apr 27, 2013 3:02 pm Post subject: |
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About the two cards using the same driver, any idea how to blacklist one card ?
I don't need that soundcard integrated to graphic card ! (can only be source of problems) |
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PaulBredbury Watchman
Joined: 14 Jul 2005 Posts: 7310
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Posted: Sat Apr 27, 2013 3:14 pm Post subject: |
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Use probe_mask, e.g. I use:
Code: | options snd-hda-intel index=0 probe_mask=1 model=acer-aspire-8930g |
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alex6 Apprentice
Joined: 18 Jul 2011 Posts: 176
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wcg Guru
Joined: 06 Jan 2009 Posts: 588
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Posted: Sat Apr 27, 2013 6:59 pm Post subject: |
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Note that the VIA VT1708S is only the codec. The actual sound card is
in your mb chipset:
http://www.hardwaresecrets.com/article/How-On-Board-Audio-Works/28
(Onboard sound in AMD and Nvidia chipsets works the same way as the
sound support in the Intel chipset used as an example in the article.) _________________ TIA |
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radio_flyer Guru
Joined: 04 Nov 2004 Posts: 317 Location: Northern California
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Posted: Wed May 08, 2013 7:45 pm Post subject: |
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It's not uncommon for my onboard HDA Intel audio to underrun after I log in to my desktop. In my case, the issue is KDE (namely nepomuk/virtuoso) doing its file scanning. On directories with lots of small files it impacts I/O processes, causing audio underruns. The underruns stop once nepomuk/virtuoso stop scanning.
Just an FYI in case you happening to be running KDE. |
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PaulBredbury Watchman
Joined: 14 Jul 2005 Posts: 7310
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Posted: Wed May 08, 2013 11:02 pm Post subject: |
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radio_flyer wrote: | KDE (namely nepomuk/virtuoso) doing its file scanning |
Then that should be run using nice and ionice - see info.
Also, sound-playing apps should have their priority boosted - again, using nice and ionice. _________________ Improve your font rendering and ALSA sound |
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radio_flyer Guru
Joined: 04 Nov 2004 Posts: 317 Location: Northern California
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Posted: Thu May 09, 2013 4:24 pm Post subject: |
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Quote: |
Then that should be run using nice and ionice - see info.
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Actually, the nepomuk and virtuoso processes ARE running at a nice level of 19 and an ionice of idle. Even though they consume around 30% on each of my four cores while they're running, they don't noticeable interfere with most desktop tasks.
The problem seems to be that even with those lowest possible nice levels some I/O subsystem itself occasionally stalls when nepomuk/virtuoso is indexing lots of small files while audio is playing at the same time. Most likely either the kernel is running out of I/O buffers, or there is some disk I/O hardware activity/stall happening. I'm fairly certain it's related to the SATA subsystem, as my disk activity LED 'hangs' lit for a second or so at the same time as the audio skips. It may just manifest itself on certain hardware/driver combinations such as my Shuttle. I haven't bothered to dig deeper, as the easy fix is to make sure nepomuk/virtuoso aren't running if the audio stutters. Nepomuk/virtuoso seem more stable on KDE 4.10, and usually finish their new-file indexing and go away a few minutes after logging in anyway. |
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PaulBredbury Watchman
Joined: 14 Jul 2005 Posts: 7310
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Posted: Thu May 09, 2013 10:30 pm Post subject: |
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Sounds like you need filesystem tweaks to prevent the audio player from being starved of data.
E.g. in /etc/fstab I use:
Code: | /dev/sda1 / ext4 defaults,noatime,commit=60,nobarrier 1 1 |
And in /etc/sysctl.conf - see info
Code: | vm.dirty_background_ratio=10
vm.dirty_ratio=30 |
_________________ Improve your font rendering and ALSA sound |
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