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-rw-r--r--arch/x86_64/kernel/time.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c
index 335cc91c49b7..9c7fba30dac1 100644
--- a/arch/x86_64/kernel/time.c
+++ b/arch/x86_64/kernel/time.c
@@ -657,6 +657,7 @@ core_initcall(cpufreq_tsc);
657 657
658#define TICK_COUNT 100000000 658#define TICK_COUNT 100000000
659#define TICK_MIN 5000 659#define TICK_MIN 5000
660#define MAX_READ_RETRIES 5
660 661
661/* 662/*
662 * Some platforms take periodic SMI interrupts with 5ms duration. Make sure none 663 * Some platforms take periodic SMI interrupts with 5ms duration. Make sure none
@@ -664,13 +665,17 @@ core_initcall(cpufreq_tsc);
664 */ 665 */
665static void __init read_hpet_tsc(int *hpet, int *tsc) 666static void __init read_hpet_tsc(int *hpet, int *tsc)
666{ 667{
667 int tsc1, tsc2, hpet1; 668 int tsc1, tsc2, hpet1, retries = 0;
669 static int msg;
668 670
669 do { 671 do {
670 tsc1 = get_cycles_sync(); 672 tsc1 = get_cycles_sync();
671 hpet1 = hpet_readl(HPET_COUNTER); 673 hpet1 = hpet_readl(HPET_COUNTER);
672 tsc2 = get_cycles_sync(); 674 tsc2 = get_cycles_sync();
673 } while (tsc2 - tsc1 > TICK_MIN); 675 } while (tsc2 - tsc1 > TICK_MIN && retries++ < MAX_READ_RETRIES);
676 if (retries >= MAX_READ_RETRIES && !msg++)
677 printk(KERN_WARNING
678 "hpet.c: exceeded max retries to read HPET & TSC\n");
674 *hpet = hpet1; 679 *hpet = hpet1;
675 *tsc = tsc2; 680 *tsc = tsc2;
676} 681}