From 1a10760c91c394dfe4adfefeeaf85cd8098c4894 Mon Sep 17 00:00:00 2001 From: Mattia Dongili Date: Fri, 2 Dec 2005 21:59:41 +0100 Subject: [CPUFREQ] Measure transition latency at driver initialization The attached patch introduces runtime latency measurement for ICH[234] based chipsets instead of using CPUFREQ_ETERNAL. It includes some sanity checks in case the measured value is out of range and assigns a safe value of 500uSec that should still be enough on problematics chipsets (current testing report values ~200uSec). The measurement is currently done in speedstep_get_freqs in order to avoid further unnecessary transitions and in the hope it'll come handy for SMI also. Signed-off-by: Mattia Dongili Acked-by: Dominik Brodowski Signed-off-by: Dave Jones speedstep-ich.c | 4 ++-- speedstep-lib.c | 32 +++++++++++++++++++++++++++++++- speedstep-lib.h | 1 + speedstep-smi.c | 1 + 4 files changed, 35 insertions(+), 3 deletions(-) --- arch/i386/kernel/cpu/cpufreq/speedstep-lib.h | 1 + 1 file changed, 1 insertion(+) (limited to 'arch/i386/kernel/cpu/cpufreq/speedstep-lib.h') diff --git a/arch/i386/kernel/cpu/cpufreq/speedstep-lib.h b/arch/i386/kernel/cpu/cpufreq/speedstep-lib.h index 261a2c9b7f6..6a727fd3a77 100644 --- a/arch/i386/kernel/cpu/cpufreq/speedstep-lib.h +++ b/arch/i386/kernel/cpu/cpufreq/speedstep-lib.h @@ -44,4 +44,5 @@ extern unsigned int speedstep_get_processor_frequency(unsigned int processor); extern unsigned int speedstep_get_freqs(unsigned int processor, unsigned int *low_speed, unsigned int *high_speed, + unsigned int *transition_latency, void (*set_state) (unsigned int state)); -- cgit v1.2.3