cpufreq fix for 3.5-rc7

This fixes a regression preventing the ACPI cpufreq driver from loading on some
systems where it worked previously without any problems.
cpufreq / ACPI: Fix not loading acpi-cpufreq driver regression

Commit d640113fe80e45ebd4a5b420b introduced a regression on SMP
systems where the processor core with ACPI id zero is disabled
(typically should be the case because of hyperthreading).
The regression got spread through stable kernels.
On 3.0.X it got introduced via 3.0.18.

Such platforms may be rare, but do exist.
Look out for a disabled processor with acpi_id 0 in dmesg:
ACPI: LAPIC (acpi_id[0x00] lapic_id[0x10] disabled)

This problem has been observed on a:
HP Proliant BL280c G6 blade

This patch restricts the introduced workaround to platforms
with nr_cpu_ids <= 1.

Signed-off-by: Thomas Renninger <trenn@suse.de>
CC: stable@vger.kernel.org
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
1 file changed