Enable ACPI PDC handshake for VIA/Centaur CPUs
authorHarald Welte <HaraldWelte@viatech.com>
Tue, 24 Nov 2009 15:53:00 +0000 (16:53 +0100)
committerGreg Kroah-Hartman <gregkh@suse.de>
Tue, 8 Dec 2009 19:17:17 +0000 (11:17 -0800)
commitfdab80d867f4df236d5158a232275147964a7705
treed30c24b907dcb0f818b4186324641cf012128553
parentf6cb332a48ed2100e820cbcae1904e3ad294ae32
Enable ACPI PDC handshake for VIA/Centaur CPUs

commit d77b81974521c82fa6fda38dfff1b491dcc62a32 upstream.

In commit 0de51088e6a82bc8413d3ca9e28bbca2788b5b53, we introduced the
use of acpi-cpufreq on VIA/Centaur CPU's by removing a vendor check for
VENDOR_INTEL.  However, as it turns out, at least the Nano CPU's also
need the PDC (processor driver capabilities) handshake in order to
activate the methods required for acpi-cpufreq.

Since arch_acpi_processor_init_pdc() contains another vendor check for
Intel, the PDC is not initialized on VIA CPU's.  The resulting behavior
of a current mainline kernel on such systems is:  acpi-cpufreq
loads and it indicates CPU frequency changes.  However, the CPU stays at
a single frequency

This trivial patch ensures that init_intel_pdc() is called on Intel and
VIA/Centaur CPU's alike.

Signed-off-by: Harald Welte <HaraldWelte@viatech.com>
Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
arch/x86/kernel/acpi/processor.c