lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

[PATCH] x86-64: - Ignore long SMI interrupts in clock calibration code - update 1

Browse Source 
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>
This commit is contained in:
Jack Steiner
2007-02-13 13:26:24 +01:00
committed by Andi Kleen
parent 6c5806cae5
commit 2f7a2a79c3
1 changed files with 7 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
arch/x86_64/kernel/time.c
View File

@@ -657,6 +657,7 @@ core_initcall(cpufreq_tsc);
#define TICK_COUNT 100000000 #define TICK_COUNT 100000000
#define TICK_MIN 5000 #define TICK_MIN 5000
#define MAX_READ_RETRIES 5
/* /*
* Some platforms take periodic SMI interrupts with 5ms duration. Make sure none * 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) static void __init read_hpet_tsc(int *hpet, int *tsc)
{ {
int tsc1, tsc2, hpet1; int tsc1, tsc2, hpet1, retries = 0;
static int msg;
do { do {
tsc1 = get_cycles_sync(); tsc1 = get_cycles_sync();
hpet1 = hpet_readl(HPET_COUNTER); hpet1 = hpet_readl(HPET_COUNTER);
tsc2 = get_cycles_sync(); 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; *hpet = hpet1;
*tsc = tsc2; *tsc = tsc2;
} }