The patch titled
i386: HPET, check if the counter works
has been added to the -mm tree. Its filename is
i386-hpet-check-if-the-counter-works.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: i386: HPET, check if the counter works
From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Some systems have a HPET which is not incrementing, which leads to a
complete hang. Detect it during HPET setup.
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxx>
Cc: john stultz <johnstul@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/i386/kernel/hpet.c | 24 +++++++++++++++++++++++-
1 files changed, 23 insertions(+), 1 deletion(-)
diff -puN arch/i386/kernel/hpet.c~i386-hpet-check-if-the-counter-works arch/i386/kernel/hpet.c
--- a/arch/i386/kernel/hpet.c~i386-hpet-check-if-the-counter-works
+++ a/arch/i386/kernel/hpet.c
@@ -226,7 +226,8 @@ int __init hpet_enable(void)
{
unsigned long id;
uint64_t hpet_freq;
- u64 tmp;
+ u64 tmp, start, now;
+ cycle_t t1;
if (!is_hpet_capable())
return 0;
@@ -273,6 +274,27 @@ int __init hpet_enable(void)
/* Start the counter */
hpet_start_counter();
+ /* Verify whether hpet counter works */
+ t1 = read_hpet();
+ rdtscll(start);
+
+ /*
+ * We don't know the TSC frequency yet, but waiting for
+ * 200000 TSC cycles is safe:
+ * 4 GHz == 50us
+ * 1 GHz == 200us
+ */
+ do {
+ rep_nop();
+ rdtscll(now);
+ } while ((now - start) < 200000UL);
+
+ if (t1 == read_hpet()) {
+ printk(KERN_WARNING
+ "HPET counter not counting. HPET disabled\n");
+ goto out_nohpet;
+ }
+
/* Initialize and register HPET clocksource
*
* hpet period is in femto seconds per cycle
_
Patches currently in -mm which might be from tglx@xxxxxxxxxxxxx are
origin.patch
arm-spinlock-initializer-cleanup.patch
git-avr32.patch
drm-spinlock-initializer-cleanup.patch
git-dvb.patch
s390-spinlock-initializer-cleanup.patch
i386-hpet-check-if-the-counter-works.patch
timer_stats-slimmed-down-using-statistics-infrastucture.patch
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