http://patchwork.kernel.org/patch/1473/ causes kernel to only use 1 cpu core on Asus M3A78 Pro motherboard
Hi, I just went through a kernel bisection to find out why my Asus M3A78
Pro motherboard with dual core AMD64 cpu was only seeing one cpu core on
2.6.29 kernels, but showed and used both cores on earlier kernels such
as 2.6.26. The kernel and applications I have been using were compiled
for x86-64 architecture (64-bit).
After bisection identified commit
7b37b5fd9ba32c0c5afc3537eed7e7466f2173e2 which added patch
http://patchwork.kernel.org/patch/1473/ I rebuilt the current 2.6.29
kernel from http://kernel-archive.buildserver.net with that patch backed
out, and again I had multiple cores available:
$ dmesg|grep SMP
[ 0.000000] Linux version 2.6.29 (2.6.29) (root@am64) (gcc version
4.3.3 (Debian 4.3.3-8) ) #1 SMP PREEMPT Sun Apr 19 02:19:00 CST 2009
[ 0.000000] found SMP MP-table at [ffff8800000ff780] 000ff780
[ 0.000000] SMP: Allowing 2 CPUs, 0 hotplug CPUs
I am happy to provide any further information to help identify why this
patch caused the kernel to only see and use one core and identify a
solution that does not cause the problems that the above patch was
designed to fix.
ACPI 2.0 is enabled in the BIOS.
I disabled ACPI APIC support in the BIOS due to disk read/write problems
and file system corruption, which I've just reported as Debian bug
#524643 http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=524643 )
The Asus M4A78A Pro motherboard manual states:
"ACPI APIC Support" When set to enabled, the ACPI APIC table pointer is
included in the RSDT pointer list.
Regards,
Arthur Marsh.
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