diff options
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kernel/tsc_msr.c | 19 |
1 files changed, 3 insertions, 16 deletions
diff --git a/arch/x86/kernel/tsc_msr.c b/arch/x86/kernel/tsc_msr.c index 4ec5e56..f7ba44b 100644 --- a/arch/x86/kernel/tsc_msr.c +++ b/arch/x86/kernel/tsc_msr.c @@ -76,9 +76,10 @@ static int match_cpu(u8 family, u8 model) (freq_desc_tables[cpu_index].freqs[freq_id]) /* - * Do MSR calibration only for known/supported CPUs. + * MSR-based CPU/TSC frequency discovery for certain CPUs. * - * Returns the calibration value or 0 if MSR calibration failed. + * Set global "lapic_timer_frequency" to bus_clock_cycles/jiffy + * Return processor base frequency in KHz, or 0 on failure. */ unsigned long try_msr_calibrate_tsc(void) { @@ -100,31 +101,17 @@ unsigned long try_msr_calibrate_tsc(void) rdmsr(MSR_IA32_PERF_STATUS, lo, hi); ratio = (hi >> 8) & 0x1f; } - pr_info("Maximum core-clock to bus-clock ratio: 0x%x\n", ratio); - - if (!ratio) - goto fail; /* Get FSB FREQ ID */ rdmsr(MSR_FSB_FREQ, lo, hi); freq_id = lo & 0x7; freq = id_to_freq(cpu_index, freq_id); - pr_info("Resolved frequency ID: %u, frequency: %u KHz\n", - freq_id, freq); - if (!freq) - goto fail; /* TSC frequency = maximum resolved freq * maximum resolved bus ratio */ res = freq * ratio; - pr_info("TSC runs at %lu KHz\n", res); #ifdef CONFIG_X86_LOCAL_APIC lapic_timer_frequency = (freq * 1000) / HZ; - pr_info("lapic_timer_frequency = %d\n", lapic_timer_frequency); #endif return res; - -fail: - pr_warn("Fast TSC calibration using MSR failed\n"); - return 0; } |
