linux

iv/linux

History

Thomas Gleixner ca1b940ce6 [PATCH] i386: trust the PM-Timer calibration of the local APIC timer

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>
Acked-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2007-03-18 11:35:08 -07:00

boot

Use ARRAY_SIZE() macro in i386 relocs.c file

2007-02-17 19:10:01 +01:00

crypto

[CRYPTO] api: Get rid of flags argument to setkey

2006-09-21 11:41:02 +10:00

kernel

[PATCH] i386: trust the PM-Timer calibration of the local APIC timer

2007-03-18 11:35:08 -07:00

lib

{rd,wr}msr_on_cpu SMP=n optimization