Re: 2.4.10 problem with APM on Inspiron 8000

Mikael Pettersson (
Sat, 29 Sep 2001 00:50:03 +0200 (MET DST)

On Fri, 28 Sep 2001 11:40:19 -0400, John Ruttenberg wrote:

>My Inspiron 8k loves kernels 2.4.* up to 2.4.9, but has problems with 2.4.10.
>In particular, it seems that any APM event (suspend, etc.) causes a hard
>freeze. In fact, on 2.4.9 and lower, I can even use the function-setup key
>which lets me examine/change bios while the kernel is running. On 2.4.10,
>this causes a kernel freeze.
>My .config files are essentially identical for 2.4.9 and for 2.4.10.
>On thing I noticed that seems a little suspicious is this start up message:
> Local APIC disabled by BIOS -- reenabling.
> Found and enabled local APIC!
>For 2.4.9, I get:
> mapped APIC to ffffe000 (01442000)

The I8000 again (sigh). You apparently have SMP or UP IOAPIC enabled.
In this case, 2.4.10 will enable the local APIC if the BIOS didn't.

To help debug the freeze, please try the patch below: it will cause
the kernel to log any APM event sent to it from the BIOS. Run this
in an SMP&UP_IOAPIC-less kernel. Do one of the actions above that
would freeze the APIC-enabled kernel (like the key sequence to enter
the BIOS setup screens). Check the kernel log. Did APM log any event,
and if so, which one?

My suspicion (from this and other reports) is that the Inspiron 8000's
BIOS SMM can't handle an enabled local APIC, or it passes an APM event
that apm.c ignores. Either case can be lethal.


--- linux-2.4.10/arch/i386/kernel/apm.c.~1~ Sun Sep 23 21:06:30 2001
+++ linux-2.4.10/arch/i386/kernel/apm.c Sat Sep 29 00:11:23 2001
@@ -927,6 +927,7 @@

static int send_event(apm_event_t event)
+ printk(__FUNCTION__ ": event %u\n", event);
switch (event) {
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