diff options
| author | Ingo Molnar <mingo@elte.hu> | 2008-04-07 20:58:08 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-04-07 21:09:14 +0200 |
| commit | 5b13d863573e746739ccfc24ac1a9473cfee8df1 (patch) | |
| tree | aa7f3536bf6f1c491a6051cf55b4ed71cd2a421c /arch/x86/kernel/tsc_32.c | |
| parent | 4cac04dd63fa3b202ee313ed1afbbd135ab887ee (diff) | |
revert "x86: tsc prevent time going backwards"
revert:
| commit 47001d603375f857a7fab0e9c095d964a1ea0039
| Author: Thomas Gleixner <tglx@linutronix.de>
| Date: Tue Apr 1 19:45:18 2008 +0200
|
| x86: tsc prevent time going backwards
it has been identified to cause suspend regression - and the
commit fixes a longstanding bug that existed before 2.6.25 was
opened - so it can wait some more until the effects are better
understood.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/tsc_32.c')
| -rw-r--r-- | arch/x86/kernel/tsc_32.c | 15 |
1 files changed, 1 insertions, 14 deletions
diff --git a/arch/x86/kernel/tsc_32.c b/arch/x86/kernel/tsc_32.c index d7498b34c8e9..f14cfd9d1f94 100644 --- a/arch/x86/kernel/tsc_32.c +++ b/arch/x86/kernel/tsc_32.c @@ -287,27 +287,14 @@ core_initcall(cpufreq_tsc); /* clock source code */ static unsigned long current_tsc_khz = 0; -static struct clocksource clocksource_tsc; -/* - * We compare the TSC to the cycle_last value in the clocksource - * structure to avoid a nasty time-warp issue. This can be observed in - * a very small window right after one CPU updated cycle_last under - * xtime lock and the other CPU reads a TSC value which is smaller - * than the cycle_last reference value due to a TSC which is slighty - * behind. This delta is nowhere else observable, but in that case it - * results in a forward time jump in the range of hours due to the - * unsigned delta calculation of the time keeping core code, which is - * necessary to support wrapping clocksources like pm timer. - */ static cycle_t read_tsc(void) { cycle_t ret; rdtscll(ret); - return ret >= clocksource_tsc.cycle_last ? - ret : clocksource_tsc.cycle_last; + return ret; } static struct clocksource clocksource_tsc = { |