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| author | Ingo Molnar <mingo@elte.hu> | 2008-09-04 22:47:47 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-09-04 23:21:57 +0200 |
| commit | 4156e9a8ef5b521185f451213d33fa661f38512e (patch) | |
| tree | d6e8df44babd295a2d9e51bf95cfec6be1d758ee /arch/x86/kernel/tsc.c | |
| parent | 6ac40ed0413ef4096720f966e11c7cdf259eee3f (diff) | |
| download | linux-4156e9a8ef5b521185f451213d33fa661f38512e.tar.gz linux-4156e9a8ef5b521185f451213d33fa661f38512e.tar.bz2 linux-4156e9a8ef5b521185f451213d33fa661f38512e.zip | |
x86: quick TSC calibration, improve
- make sure the final TSC timestamp is reliable too
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/tsc.c')
| -rw-r--r-- | arch/x86/kernel/tsc.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index 839070ba8465..6dab90f68515 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -317,6 +317,12 @@ static unsigned long quick_pit_calibrate(void) t2 = get_cycles(); /* + * Make sure we can rely on the second TSC timestamp: + */ + if (!pit_expect_msb(--expect)) + goto failed; + + /* * Ok, if we get here, then we've seen the * MSB of the PIT decrement QUICK_PIT_ITERATIONS * times, and each MSB had many hits, so we never |