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* Thomas Gleixner <tglx@linutronix.de> wrote: > When PM-Timer is available for local APIC timer calibration we can > skip the verification of the calibrated time value. The resulting > error is quite small on a bunch of evaluated platforms and is less > harming than the observed false positives. > > We need to keep the verification on systems, which have no PM-Timer to > avoid bogus local APIC timer calibrations in the range of factor 2-10, > which can be observed when swicthing off the PM-timer support in the > kernel configuration. > > The wrong calibration values are probably caused by SMM code trying to > emulate a PS/2 keyboard from a (maybe connected or not) USB keyboard. > This prohibits the accurate delivery of PIT interrupts, which are used > to calibrate the local APIC timer. Unfortunately we have no way to > disable this BIOS misfeature in the early boot process. > > Add also the dropped cpu_relax() back to the wait loops. > > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@elte.hu> Ingo - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||
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