The patch titled
HPET RTC emulation: add watchdog timer
has been removed from the -mm tree. Its filename is
hpet-rtc-emulation-add-watchdog-timer.patch
This patch was dropped because an updated version was merged
------------------------------------------------------
Subject: HPET RTC emulation: add watchdog timer
From: Clemens Ladisch <clemens@xxxxxxxxxx>
To prevent the emulated RTC timer from stopping when interrupts are
disabled for too long, implement the watchdog timer to restart it when
needed.
Andi: "The interrupt handler should just read the time (it likely has
to do that anyways) and check for that directly. That is what I did in
my noidletick HPET patch and it worked ok."
Signed-off-by: Clemens Ladisch <clemens@xxxxxxxxxx>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@xxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxx>
Cc: Vojtech Pavlik <vojtech@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
arch/i386/kernel/time_hpet.c | 36 +++++++++++++++++++++++++++++++++
arch/x86_64/kernel/time.c | 36 +++++++++++++++++++++++++++++++++
2 files changed, 72 insertions(+)
diff -puN arch/i386/kernel/time_hpet.c~hpet-rtc-emulation-add-watchdog-timer arch/i386/kernel/time_hpet.c
--- a/arch/i386/kernel/time_hpet.c~hpet-rtc-emulation-add-watchdog-timer
+++ a/arch/i386/kernel/time_hpet.c
@@ -411,9 +411,45 @@ int hpet_set_periodic_freq(unsigned long
int hpet_rtc_dropped_irq(void)
{
+ unsigned int cnt, ticks_per_int, lost_ints;
+
if (!is_hpet_enabled())
return 0;
+ if (UIE_on | PIE_on | AIE_on) {
+ /*
+ * The interrupt handler schedules the next interrupt at a
+ * constant offset from the time the current interrupt was
+ * scheduled, without regard to the actual time. When the
+ * handler is delayed too long, it tries to schedule the next
+ * interrupt in the past and the hardware would not interrupt
+ * until the counter had wrapped around. We catch it here.
+ */
+ cnt = hpet_readl(HPET_COUNTER);
+ /* was the comparator set to a time in the past? */
+ if ((int)(cnt - hpet_t1_cmp) > 0) {
+ /* determine how many interrupts were actually lost */
+ ticks_per_int = (hpet_tick * HZ) / hpet_rtc_int_freq;
+ lost_ints = (cnt - hpet_t1_cmp) / ticks_per_int + 1;
+ /*
+ * Make sure that, even with the time needed to execute
+ * this code, the next scheduled interrupt has been
+ * moved back to the future.
+ */
+ lost_ints++;
+
+ cnt = hpet_t1_cmp + lost_ints * ticks_per_int;
+ hpet_writel(cnt, HPET_T1_CMP);
+ hpet_t1_cmp = cnt;
+
+ if (PIE_on)
+ PIE_count += lost_ints;
+
+ printk(KERN_WARNING "rtc: lost some interrupts"
+ " at %ldHz.\n", hpet_rtc_int_freq);
+ }
+ }
+
return 1;
}
diff -puN arch/x86_64/kernel/time.c~hpet-rtc-emulation-add-watchdog-timer arch/x86_64/kernel/time.c
--- a/arch/x86_64/kernel/time.c~hpet-rtc-emulation-add-watchdog-timer
+++ a/arch/x86_64/kernel/time.c
@@ -1249,9 +1249,45 @@ int hpet_set_periodic_freq(unsigned long
int hpet_rtc_dropped_irq(void)
{
+ unsigned int cnt, ticks_per_int, lost_ints;
+
if (!is_hpet_enabled())
return 0;
+ if (UIE_on | PIE_on | AIE_on) {
+ /*
+ * The interrupt handler schedules the next interrupt at a
+ * constant offset from the time the current interrupt was
+ * scheduled, without regard to the actual time. When the
+ * handler is delayed too long, it tries to schedule the next
+ * interrupt in the past and the hardware would not interrupt
+ * until the counter had wrapped around. We catch it here.
+ */
+ cnt = hpet_readl(HPET_COUNTER);
+ /* was the comparator set to a time in the past? */
+ if ((int)(cnt - hpet_t1_cmp) > 0) {
+ /* determine how many interrupts were actually lost */
+ ticks_per_int = (hpet_tick * HZ) / hpet_rtc_int_freq;
+ lost_ints = (cnt - hpet_t1_cmp) / ticks_per_int + 1;
+ /*
+ * Make sure that, even with the time needed to execute
+ * this code, the next scheduled interrupt has been
+ * moved back to the future.
+ */
+ lost_ints++;
+
+ cnt = hpet_t1_cmp + lost_ints * ticks_per_int;
+ hpet_writel(cnt, HPET_T1_CMP);
+ hpet_t1_cmp = cnt;
+
+ if (PIE_on)
+ PIE_count += lost_ints;
+
+ printk(KERN_WARNING "rtc: lost some interrupts"
+ " at %ldHz.\n", hpet_rtc_int_freq);
+ }
+ }
+
return 1;
}
_
Patches currently in -mm which might be from clemens@xxxxxxxxxx are
origin.patch
hpet-rtc-emulation-add-watchdog-timer.patch
-
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
