[alsa-devel] 2.6.34-rc1: regression: ^Z no longer stops sound

Bill Davidsen davidsen at tmr.com
Wed Mar 24 17:47:37 CET 2010

Clemens Ladisch wrote:
> Pavel Machek wrote:
>> On Sun 2010-03-14 17:20:13, Bill Davidsen wrote:
>>> Pavel Machek wrote:
>>>> In 2.6.33, hitting ^Z stopped mpg123 in a way you'd expect (both on
>>>> thinkpad and geode notebook).
>>>> On 2.6.34-rc1, hit ^Z and sound starts looping.
>>> That's not new, I have seen it back as far as doing a suspend 
>>> in a VM (KVM, no libvirt). But it only happens a few times a year, so I 
>>> never chased it. I hate to report an occasional problem in an obsolete 
>>> kernel, and I can't reproduce it.
>>> Does it happen repeatably with the new kernel?
>> It happened reliably so far, yes.
> This sounds as if the device has been configured to ignore underruns.
> What are the contents of /proc/asound/card0/pcm0p/sub0/{sw_params,status}
> when it's looping, and when it's really suspended?

If you can give me a hint how to read /proc when the machine is 
suspended, other than waking it up, I'll certainly check the next time I 
see it.

But after reading your thought on underruns, I think you right. I see 
from a note  I wrote myself that I get this while pushing a wav file 
over the network to run "play" (from sox) on another machine. Every once 
in a while it finds a musical phrase it really likes. I had assumed it 
was a bug in sox, but a bug or mis-configure in the device fits all of 
the observed cases I've seen.

Bill Davidsen <davidsen at tmr.com>
  "We can't solve today's problems by using the same thinking we
   used in creating them." - Einstein

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