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. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Thu Mar 15 2001 - 21:00:11 EST