Subject: Re: 2.6.15-rt20, "bad page state", jackd
From: Fernando Lopez-Lezcano <nando@ccrma.Stanford.EDU>
To: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: alsa-devel@lists.sourceforge.net, Ingo Molnar <mingo@elte.hu>,
       Heiko Carstens <heiko.carstens@de.ibm.com>,
       Steven Rostedt <rostedt@goodmis.org>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
In-Reply-To: <4410B2D7.4090806@yahoo.com.au>
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Date: Thu, 09 Mar 2006 18:47:46 -0800
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On Fri, 2006-03-10 at 09:57 +1100, Nick Piggin wrote:
> Fernando Lopez-Lezcano wrote:
> 
> > In my case it is completely repeatable. 
> > Boot, start jackd, stop jackd -> problem appears. 
> > 
> > This does not happen on all computers so it would seem to me it is
> > related to the sound drivers. I'll try to see if there is a correlation
> > with the sound card being used. 
> > 
> > Is there anything else I could do to try to help resolve this?
> 
> Can you test with the latest mainline -git snapshot, or is it only
> the -rt tree that causes the warnings?

I found something strange although I don't know why it happens yet:

  Fedora Core 4 kernel (2.6.15 + patches) works fine.
  Fedora Core 4 kernel + -rt21, [ahem... sorry], works fine.
  Fedora Core 4 kernel + -rt21 + alsa kernel modules from 1.0.10 or
     1.0.11rc3, fails[*]
  Plain vanilla 2.6.15 + -rt21, works fine
  Plain vanilla 2.6.15 + -rt21 + alsa kernel modules from 1.0.10 or
     1.0.11rc3, fails[*]

So, it looks like it is some weird interaction between kernel modules
that were not compiled as part of the kernel and the kernel itself. The
"updated" modules are installed in a separate location (not on top of
the built in kernel modules) and are found before the ones in the kernel
tree.

I have been building this combination for a long long time with no
problems, I don't know what might have happened that changed things.

Could be:
- configuration problems?
- the alsa tree is somehow incompatible with the kernel alsa tree, is
  that even possible?

I have _no_ idea on what to start looking for... but, oh well, this is a
start. Suggestions welcome. Thanks for somehow pointing me in the right
direction. 

-- Fernando

[*] I need that because of cards not yet included in the kernel proper,
and fixes that have not yet percolated to the kernel alsa tree. 


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