Date: Mon, 25 Oct 2004 15:07:03 -0400 (EDT)
From: linux-os <root@analogic.com>
Reply-To: linux-os@analogic.com
To: Lee Revell <rlrevell@joe-job.com>
cc: Linux kernel <linux-kernel@vger.kernel.org>
Subject: Re: printk() with a spin-lock held.
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On Mon, 25 Oct 2004, Lee Revell wrote:

> On Mon, 2004-10-25 at 08:32 -0400, Richard B. Johnson wrote:
>> I recall that printk() useds to just write stuff into a buffer,
>> that the buffer (the same buffer used for dmesg), was written
>> out only when it was safe to do so.
>>
>>
>> Now, if printk() can't do that anymore, how does one de-bug
>> ISR code? Or do you just heave it off the cliff and hope that
>> it flies?
>
> No, it can, I was wrong.  I was thinking of some other function.
>
> Lee

Yes. I think that the problem I observed was when the ISR
wouldn't reset the interrupt because the hardware was broken.
This makes the level-interrupt stay active forever. I put
a printk() in the ISR and I got a bug-check because printk
didn't like me.

Apparently, if the printk() buffer gets full, it bug-checks.
The behavior used to be that it would just dump overflow
on the floor.

Cheers,
Dick Johnson
Penguin : Linux version 2.6.9 on an i686 machine (5537.79 GrumpyMips).
                  98.36% of all statistics are fiction.
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