On Sat, Jan 25, 2014 at 01:09:23AM -0800, Bin Gao wrote: > > diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index > > a3acbac2ee72$ > > --- a/arch/x86/kernel/tsc.c > > +++ b/arch/x86/kernel/tsc.c > > @@ -655,10 +655,11 @@ unsigned long native_calibrate_tsc(void) > > local_irq_save(flags); > > i = try_msr_calibrate_tsc(&fast_calibrate); > > local_irq_restore(flags); > > - if (i >= 0) { > > - if (i == 0) > > - pr_warn("Fast TSC calibration using MSR failed\n"); > > + if (i > 0) { > > return fast_calibrate; > > + } else if (i == 0) { > > + pr_warn("Fast TSC calibration using MSR failed\n"); > > + /* Continue with the normal calibration */ > > } > > > > local_irq_save(flags); > > The original design is to avoid trying PIC because touching PIC on > a non-PIC SoC will simply cause system hang. Returning 0 will cause > kernel to mark TSC unstable(rating 0). Since PM timer and HPET are > typically not available on non-PIC SoC, kernal falls back to jiffies > as clock source. Developers will start looking into the TSC clibrating > failure once they notice the jiffies clock source. > > >[<ffffffff810aecb0>] clockevents_config_and_register+0x20/0x30 > >[<ffffffff81030168>] setup_APIC_timer+0xc8/0xd0 > >[<ffffffff81d1104f>] setup_boot_APIC_clock+0x4cc/0x4d8 > >[<ffffffff81d0f5de>] native_smp_prepare_cpus+0x3dd/0x3f0 > >[<ffffffff81d02ee9>] kernel_init_freeable+0xc3/0x205 > >[<ffffffff8177c910>] ? rest_init+0x90/0x90 > >[<ffffffff8177c91e>] kernel_init+0xe/0x120 > >[<ffffffff8178deec>] ret_from_fork+0x7c/0xb0 > >[<ffffffff8177c910>] ? rest_init+0x90/0x90 > > This is because kernel is trying to use tsc-deadline mode for lapic > timer. I think the right fix is to unset X86_FEATURE_TSC_DEADLINE_TIMER > when try_msr_calibrate_tsc() returns 0.
You are right, that works too: [ 0.000000] Resolved frequency ID: 0, frequency: 0 KHz [ 0.000000] tsc: Fast TSC calibration using MSR failed [ 0.000000] tsc: Fast TSC calibration using PIT [ 0.000000] tsc: Detected 1833.334 MHz processor If there are no objections, I can send a new version of the patch with this fixed. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/