[ltp] APM suspend with 2.6 kernel [long]

[Thomas Hood]

On Mon, 2004-01-05 at 00:02, Michael Hagemann wrote: 
> All right, I have pretty much isolated the problem.  The culprit is
> somewhere in the "big IRQ lock" patchset.

It certainly helps to know that this patch caused the problem.
However, we still have a non-trivial task ahead of us to figure
out exactly what is wrong.

We know that this patch changes the way Linux affects "things"
(where 'things' here denotes anything to which the firmware might
be paying attention) and that post-2.5.27 Linux leaves something
in a state that fails to satisfy the firmware.

But what is the important thing?  That patchset has a big footprint.
Yet I have looked through it and I don't see anything that obviously
could cause our problem.

Has anyone tried disabling preemption to see whether that helps?


> There's also the following treacherous log entry:
>
>  spurious 8259A interrupt: IRQ7

I see this without attempting a suspend.  It happens once in a while
without any obvious cause:

/var/log$ zgrep 8259A syslog*
syslog:Jan  5 13:06:26 ths kernel: spurious 8259A interrupt: IRQ7.
syslog.1.gz:Jan  3 00:18:13 ths kernel: spurious 8259A interrupt: IRQ7.
syslog.2.gz:Dec 31 13:37:39 ths kernel: spurious 8259A interrupt: IRQ7.
syslog.3.gz:Dec 24 10:28:48 ths kernel: spurious 8259A interrupt: IRQ7.
syslog.3.gz:Dec 25 13:56:52 ths kernel: spurious 8259A interrupt: IRQ7.
syslog.4.gz:Dec 23 10:34:36 ths kernel: spurious 8259A interrupt: IRQ7.
syslog.4.gz:Dec 23 16:33:47 ths kernel: spurious 8259A interrupt: IRQ7.

See the following for info:

    http://www.linuxchix.org/pipermail/techtalk/2002-August/012697.html
    http://linux-kernel.skylab.org/20011125/msg01748.html

-- 
Thomas Hood <jdthood2@yahoo.co.uk>