From: Jason McMullan <jmcmullan@linuxcare.com>
To: linux-kernel@vger.kernel.org
Subject: SMP and APM
Date: 10 Mar 2001 06:06:31 GMT [thread overview]
Message-ID: <98cg97$3mp$1@dhcp24.resilience.com> (raw)
I'm working on a BIOS for a SMP machine, and I was
wondering if the following technique would allow us to
use APM _safely_ under SMP for Linux 2.4.x. APM (or -yech-
ACPI) suspend is necessary for a customer's feature, and
SMP support is required.
APM Idle calls are _not_ supported on the box, only
APM suspend. So we can take a goodly amount of time _doing_
the APM call. (I know about the long AP INIT times) We just
need to do it.
Besides, it'd be a great start for all those SMP
laptops out there. ;^)
BP - Boot Processor (CPU 0)
AP - Application Processor (CPU 1...N)
APM32 Call Flow
---------------
* APs disable their interrupts
* APs save their Local APIC tables
* APs halt
* BP calls APM32 BIOS entry point
* BP gets back from APM32 call.
* APs get INITed (arch/i386/kernel/smpboot.c:do_boot_cpu())
* APs reload their saved APICs
* APs restart interrupts
* BP and APs continue on their merry ways
--
Jason McMullan, Senior Linux Consultant
Linuxcare, Inc. 412.422.8077 tel, 412.656.3519 cell
jmcmullan@linuxcare.com, http://www.linuxcare.com/
Linuxcare. Putting open source to work.
reply other threads:[~2001-03-10 6:07 UTC|newest]
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