diff options
Diffstat (limited to 'arch/x86_64/kernel/apic.c')
| -rw-r--r-- | arch/x86_64/kernel/apic.c | 33 |
1 files changed, 27 insertions, 6 deletions
diff --git a/arch/x86_64/kernel/apic.c b/arch/x86_64/kernel/apic.c index 673a2fe9923..c02218b3ae2 100644 --- a/arch/x86_64/kernel/apic.c +++ b/arch/x86_64/kernel/apic.c @@ -40,6 +40,7 @@ int apic_verbosity; int apic_runs_main_timer; +int apic_calibrate_pmtmr __initdata; int disable_apic_timer __initdata; @@ -746,14 +747,27 @@ static int __init calibrate_APIC_clock(void) __setup_APIC_LVTT(1000000000); apic_start = apic_read(APIC_TMCCT); - rdtscl(tsc_start); - - do { +#ifdef CONFIG_X86_PM_TIMER + if (apic_calibrate_pmtmr && pmtmr_ioport) { + pmtimer_wait(5000); /* 5ms wait */ apic = apic_read(APIC_TMCCT); - rdtscl(tsc); - } while ((tsc - tsc_start) < TICK_COUNT && (apic - apic_start) < TICK_COUNT); + result = (apic_start - apic) * 1000L / 5; + } else +#endif + { + rdtscl(tsc_start); + + do { + apic = apic_read(APIC_TMCCT); + rdtscl(tsc); + } while ((tsc - tsc_start) < TICK_COUNT && + (apic - apic_start) < TICK_COUNT); + + result = (apic_start - apic) * 1000L * cpu_khz / + (tsc - tsc_start); + } + printk("result %d\n", result); - result = (apic_start - apic) * 1000L * cpu_khz / (tsc - tsc_start); printk(KERN_INFO "Detected %d.%03d MHz APIC timer.\n", result / 1000 / 1000, result / 1000 % 1000); @@ -1115,6 +1129,13 @@ static __init int setup_noapicmaintimer(char *str) } __setup("noapicmaintimer", setup_noapicmaintimer); +static __init int setup_apicpmtimer(char *s) +{ + apic_calibrate_pmtmr = 1; + return setup_apicmaintimer(NULL); +} +__setup("apicpmtimer", setup_apicpmtimer); + /* dummy parsing: see setup.c */ __setup("disableapic", setup_disableapic); |