Re: 2.6.15-rt16: possible sound-related side-effect

[Steven Rostedt <rostedt@goodmis.org>]

On Fri, 10 Feb 2006, Jonathan Woithe wrote:

> Hi all
>
> In the last week I have updated the kernel on our laptop to 2.6.15-rt16.
> By and large this worked well and had the attractive side effect of making
> the clock run at the correct speed once more.
>
> During development of an ALSA patch I had the need to remove and reinsert
> the hda-intel and hda-codec modules on numerous occasions.  Every so often
> (perhaps once every 5 or 6 times on average) the initialisation sequence of
> hda-intel would get hung up and the associated insmod would never return.  A
> reboot was required to clear the problem.  The following messages were
> written to syslog repeatedly and often:
>
>   Feb  5 21:36:24: ALSA sound/pci/hda/hda_intel.c:511: azx_get_response timeout
>   Feb  5 21:36:26 halite last message repeated 9 times
>   Feb  5 21:36:29 halite kernel: printk: 31 messages suppressed.
>
> I have noticed the "azx_get_response timeout" messages in earlier kernels
> as well, but up until now the hda initialisation hasn't gotten hung up.
>
> The latching up of the hda-intel initialisation does not appear to occur
> when doing the same thing under a non-RT 2.6.15 kernel.  Furthermore, I have
> had an instance where the lockup occured while cold-booting an unmodified
> 2.6.15-rt16, which rules out any changes I made to ALSA as the cause of the
> problem.  In any case the changes I was making to ALSA don't affect the
> initialisation code.
>
> Prior to this kernel I was running an unmodified 2.6.14-rt21 kernel and
> while these messages did occur they didn't cause hda-intel to lock up.
>
> Any suggestions as to what might be causing this and/or of further tests
> which might help narrow down the cause?

Could you turn on nmi_watchdog as well as softlockup_detect.

nmi_watchedog:
  make sure CONFIG_X86_LOCAL_APIC is set, and then pass in the command
  line "nmi_watchdog=2 lapic"  (lapic may or may not be needed, but should
  not hurt to include it).

softlockup_detect:
  set CONFIG_DETECT_SOFTLOCKUP.

these may point out better what is locked up.

-- Steve
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