linux/arch/i386/kernel/cpu/cpufreq/speedstep-lib.h
Mattia Dongili 1a10760c91 [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 <malattia@linux.it>
Acked-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Dave Jones <davej@redhat.com>

 speedstep-ich.c |    4 ++--
 speedstep-lib.c |   32 +++++++++++++++++++++++++++++++-
 speedstep-lib.h |    1 +
 speedstep-smi.c |    1 +
 4 files changed, 35 insertions(+), 3 deletions(-)
2005-12-06 19:27:15 -08:00

49 lines
1.7 KiB
C

/*
* (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
*
* Licensed under the terms of the GNU GPL License version 2.
*
* Library for common functions for Intel SpeedStep v.1 and v.2 support
*
* BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
*/
/* processors */
#define SPEEDSTEP_PROCESSOR_PIII_C_EARLY 0x00000001 /* Coppermine core */
#define SPEEDSTEP_PROCESSOR_PIII_C 0x00000002 /* Coppermine core */
#define SPEEDSTEP_PROCESSOR_PIII_T 0x00000003 /* Tualatin core */
#define SPEEDSTEP_PROCESSOR_P4M 0x00000004 /* P4-M */
/* the following processors are not speedstep-capable and are not auto-detected
* in speedstep_detect_processor(). However, their speed can be detected using
* the speedstep_get_processor_frequency() call. */
#define SPEEDSTEP_PROCESSOR_PM 0xFFFFFF03 /* Pentium M */
#define SPEEDSTEP_PROCESSOR_P4D 0xFFFFFF04 /* desktop P4 */
/* speedstep states -- only two of them */
#define SPEEDSTEP_HIGH 0x00000000
#define SPEEDSTEP_LOW 0x00000001
/* detect a speedstep-capable processor */
extern unsigned int speedstep_detect_processor (void);
/* detect the current speed (in khz) of the processor */
extern unsigned int speedstep_get_processor_frequency(unsigned int processor);
/* detect the low and high speeds of the processor. The callback
* set_state"'s first argument is either SPEEDSTEP_HIGH or
* SPEEDSTEP_LOW; the second argument is zero so that no
* cpufreq_notify_transition calls are initiated.
*/
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));