2.6.34-rc1: regression: ^Z no longer stops sound

2.6.34-rc1: regression: ^Z no longer stops sound

[Pavel Machek]

Hi!

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.
									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: 2.6.34-rc1: regression: ^Z no longer stops sound

[Bill Davidsen]

Pavel Machek wrote:
> Hi!
> 
> 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.
> 									Pavel
That's not new, I have seen it back as far as 2.6.27.25 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?

-- 
Bill Davidsen <davidsen@tmr.com>
   "We have more to fear from the bungling of the incompetent than from
the machinations of the wicked."  - from Slashdot

Re: 2.6.34-rc1: regression: ^Z no longer stops sound

[Pavel Machek]

On Sun 2010-03-14 17:20:13, Bill Davidsen wrote:
> Pavel Machek wrote:
>> Hi!
>>
>> 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.
>> 									Pavel
> That's not new, I have seen it back as far as 2.6.27.25 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.

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: 2.6.34-rc1: regression: ^Z no longer stops sound

[Clemens Ladisch]

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 2.6.27.25 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?


Regards,
Clemens

Re: 2.6.34-rc1: regression: ^Z no longer stops sound

[Bill Davidsen]

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 2.6.27.25 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@tmr.com>
  "We can't solve today's problems by using the same thinking we
   used in creating them." - Einstein

Re: 2.6.34-rc1: regression: ^Z no longer stops sound

[Takashi Iwai]

At Sun, 14 Mar 2010 08:58:31 +0100,
Pavel Machek wrote:
> 
> Hi!
> 
> 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.

Is it an OSS app using the kernel OSS emulation or another backend?

The possible cause is the rewrite of PCM hwptr updater.
Jaroslav, could you take a look?


thanks,

Takashi

Re: 2.6.34-rc1: regression: ^Z no longer stops sound

[Pavel Machek]

> At Sun, 14 Mar 2010 08:58:31 +0100,
> Pavel Machek wrote:
> > 
> > Hi!
> > 
> > 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.
> 
> Is it an OSS app using the kernel OSS emulation or another backend?

OSS kernel emulation, yes. ... at least I think I'm using it.

> The possible cause is the rewrite of PCM hwptr updater.
> Jaroslav, could you take a look?

									Pavel

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: 2.6.34-rc1: regression: ^Z no longer stops sound

[Jaroslav Kysela]

On Mon, 15 Mar 2010, Pavel Machek wrote:

>> At Sun, 14 Mar 2010 08:58:31 +0100,
>> Pavel Machek wrote:
>>>
>>> Hi!
>>>
>>> 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.
>>
>> Is it an OSS app using the kernel OSS emulation or another backend?
>
> OSS kernel emulation, yes. ... at least I think I'm using it.

I cannot reproduce this problem here. Could you post the contents
of /proc/asound/card0/pcm0p/sub0/status file when you stop the 
audio process and looping starts?

 				Thanks,
 					Jaroslav

-----
Jaroslav Kysela <perex@perex.cz>
Linux Kernel Sound Maintainer
ALSA Project, Red Hat, Inc.