x86: use the correct cpuid method to detect MWAIT support for C states
authorAndi Kleen <ak@suse.de>
Wed, 30 Jan 2008 12:33:16 +0000 (13:33 +0100)
committerIngo Molnar <mingo@elte.hu>
Wed, 30 Jan 2008 12:33:16 +0000 (13:33 +0100)
commit0c07ee38c9d4eb081758f5ad14bbffa7197e1aec
treef32f5dba9b03b9fa5ac262a2c569b43ae9d0994e
parent30d432dfab2bcfd021d352e2058fae6b9405caeb
x86: use the correct cpuid method to detect MWAIT support for C states

Previously there was a AMD specific quirk to handle the case of
AMD Fam10h MWAIT not supporting any C states. But it turns out
that CPUID already has ways to detectly detect that without
using special quirks.

The new code simply checks if MWAIT supports at least C1 and doesn't
use it if it doesn't. No more vendor specific code.

Note this is does not simply clear MWAIT because MWAIT can be still
useful even without C states.

Credit goes to Ben Serebrin for pointing out the (nearly) obvious.

Cc: "Andreas Herrmann" <andreas.herrmann3@amd.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
arch/x86/kernel/cpu/amd.c
arch/x86/kernel/process_32.c
arch/x86/kernel/process_64.c
arch/x86/kernel/setup_64.c