diff options
| author | Jack Steiner <steiner@sgi.com> | 2007-02-13 13:26:24 +0100 |
|---|---|---|
| committer | Andi Kleen <andi@basil.nowhere.org> | 2007-02-13 13:26:24 +0100 |
| commit | 2f7a2a79c3ebb44f8b1b7d9b4fd3a650eb69e544 (patch) | |
| tree | 9f68a5db49a92991b85101e4d4cbd423822abb8c /arch/x86_64/kernel/time.c | |
| parent | 6c5806cae50717f31878d0da29109b10610ab862 (diff) | |
| download | linux-2f7a2a79c3ebb44f8b1b7d9b4fd3a650eb69e544.tar.gz | |
[PATCH] x86-64: - Ignore long SMI interrupts in clock calibration code - update 1
Add failsafe mechanism to HPET/TSC clock calibration.
Signed-off-by: Jack Steiner <steiner@sgi.com>
Updated to include failsafe mechanism & additional community feedback.
Patch built on latest 2.6.20-rc4-mm1 tree.
Signed-off-by: Andi Kleen <ak@suse.de>
Diffstat (limited to 'arch/x86_64/kernel/time.c')
| -rw-r--r-- | arch/x86_64/kernel/time.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c index 335cc91c49b722..9c7fba30dac120 100644 --- a/arch/x86_64/kernel/time.c +++ b/arch/x86_64/kernel/time.c @@ -657,6 +657,7 @@ core_initcall(cpufreq_tsc); #define TICK_COUNT 100000000 #define TICK_MIN 5000 +#define MAX_READ_RETRIES 5 /* * Some platforms take periodic SMI interrupts with 5ms duration. Make sure none @@ -664,13 +665,17 @@ core_initcall(cpufreq_tsc); */ static void __init read_hpet_tsc(int *hpet, int *tsc) { - int tsc1, tsc2, hpet1; + int tsc1, tsc2, hpet1, retries = 0; + static int msg; do { tsc1 = get_cycles_sync(); hpet1 = hpet_readl(HPET_COUNTER); tsc2 = get_cycles_sync(); - } while (tsc2 - tsc1 > TICK_MIN); + } while (tsc2 - tsc1 > TICK_MIN && retries++ < MAX_READ_RETRIES); + if (retries >= MAX_READ_RETRIES && !msg++) + printk(KERN_WARNING + "hpet.c: exceeded max retries to read HPET & TSC\n"); *hpet = hpet1; *tsc = tsc2; } |