x86: HPET force enable o ICH7 and later
authorVenki Pallipadi <venkatesh.pallipadi@intel.com>
Fri, 12 Oct 2007 21:04:23 +0000 (23:04 +0200)
committerThomas Gleixner <tglx@inhelltoy.tec.linutronix.de>
Fri, 12 Oct 2007 21:04:23 +0000 (23:04 +0200)
commitd54bd57d6580250e6551261f3b15c45a9d90c77b
tree12cb06b4adb9494e67cefdc691643e333fef3b91
parent610bf2f143b9c5cda768a2d428d66d3a16769930
x86: HPET force enable o ICH7 and later

Force detect and/or enable HPET on ICH chipsets.  This patch just handles the
detection part and following patches use this information.  Adds a function to
repeat the force enabling during resume time.

Using HPET this way, instead of PIT increases the time CPUs can reside in
C-state when system is totally idle.  On my test system with Core 2 Duo,
average C-state residency goes up from ~20mS to ~80mS.

[ Build fixed from Andrew Morton ]

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Andi Kleen <ak@suse.de>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
arch/x86/kernel/quirks.c
include/asm-x86/hpet.h