linux-next - strange audio bug

linux-next - strange audio bug

[Valdis Kletnieks]

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Next-20150310 works OK, next-20150324 has the bug.

Dell Latitude E6530 laptop, lspci tells me:

01:00.1 Audio device: NVIDIA Corporation GF108 High Definition Audio Controller (rev a1)
        Subsystem: Dell Device 0535
        ...
        Kernel driver in use: snd_hda_intel

Symptoms:  Audio works perfectly at boot, and for some amount
of time after.  But somewhere around 6-8 hours of uptime, it gets
into a strange state where I'll get no audio... and then it will
cut in for all of 2 seconds or so (fairly consistent, that part),
and then cut back out for anywhere from 10 seconds to a minute,
then another 2 seconds of sound.. lather rinse repeat.

Before I start the thankless task of bisecting this (which means I'll
be able to do only 1, *maybe* 2 steps a day), does this ring any bells?

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Re: [alsa-devel] linux-next - strange audio bug

[Valdis.Kletnieks]

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On Fri, 03 Apr 2015 08:44:12 +0800, Hui Wang said:

> It sounds like the suspend or resume of power management introduces this
> problem. Probably you could reproduce this problem very soon just
> repeatedly suspend and resume the system.

I don't do suspend on this laptop, I poweroff and reboot when I get
wherever I'm going.

However... device-level power management? Hmm..  I *do* remember that
each time I found it dead, I was coming back to my laptop from doing something
else, so the sound would have been idle....

commit c4c2533f802d6877803c4d778def43d8a122f27b
Author: Takashi Iwai <tiwai@suse.de>
Date:   Tue Mar 3 17:22:12 2015 +0100

    ALSA: hda - Fix possible runtime PM refcount unbalance

That landed in next-20150324 - which is broken for me.

Looks worth trying a revert before I bisect, thanks for the hint, will
report back (probably tomorrow) on what happens...

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Re: linux-next - strange audio bug

[Takashi Iwai]

At Thu, 02 Apr 2015 20:34:35 -0400,
Valdis Kletnieks wrote:
> 
> Next-20150310 works OK, next-20150324 has the bug.
> 
> Dell Latitude E6530 laptop, lspci tells me:
> 
> 01:00.1 Audio device: NVIDIA Corporation GF108 High Definition Audio Controller (rev a1)
>         Subsystem: Dell Device 0535
>         ...
>         Kernel driver in use: snd_hda_intel
> 
> Symptoms:  Audio works perfectly at boot, and for some amount
> of time after.  But somewhere around 6-8 hours of uptime, it gets
> into a strange state where I'll get no audio... and then it will
> cut in for all of 2 seconds or so (fairly consistent, that part),
> and then cut back out for anywhere from 10 seconds to a minute,
> then another 2 seconds of sound.. lather rinse repeat.
> 
> Before I start the thankless task of bisecting this (which means I'll
> be able to do only 1, *maybe* 2 steps a day), does this ring any bells?

Try for-next branch of sound git tree
   git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git

Now I merged fixes that might be relevant with the runtime PM on some
codecs, so it might work better.

In anyway, please give alsa-info.sh outputs at good and bad-working
states.


thanks,

Takashi