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authorDavid Brownell <dbrownell@users.sourceforge.net>2008-07-23 21:30:47 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-24 10:47:34 -0700
commit7e2a31da854dcf8324012a83a31b40bc11e52589 (patch)
treefb982e22f3d9ac6ec2fc67a96a297dc743ef67e6 /arch
parent449321b39f6c6ebfa15d6da24f134240bd51db29 (diff)
rtc-cmos: avoid spurious irqs
This fixes kernel http://bugzilla.kernel.org/show_bug.cgi?id=11112 (bogus RTC update IRQs reported) for rtc-cmos, in two ways: - When HPET is stealing the IRQs, use the first IRQ to grab the seconds counter which will be monitored (instead of using whatever was previously in that memory); - In sane IRQ handling modes, scrub out old IRQ status before enabling IRQs. That latter is done by tightening up IRQ handling for rtc-cmos everywhere, also ensuring that when HPET is used it's the only thing triggering IRQ reports to userspace; net object shrink. Also fix a bogus HPET message related to its RTC emulation. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Report-by: W Unruh <unruh@physics.ubc.ca> Cc: Andrew Victor <avictor.za@gmail.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/hpet.c10
1 files changed, 7 insertions, 3 deletions
diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index 0ea6a19bfdf..ad2b15a1334 100644
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -468,7 +468,7 @@ void hpet_disable(void)
#define RTC_NUM_INTS 1
static unsigned long hpet_rtc_flags;
-static unsigned long hpet_prev_update_sec;
+static int hpet_prev_update_sec;
static struct rtc_time hpet_alarm_time;
static unsigned long hpet_pie_count;
static unsigned long hpet_t1_cmp;
@@ -575,6 +575,9 @@ int hpet_set_rtc_irq_bit(unsigned long bit_mask)
hpet_rtc_flags |= bit_mask;
+ if ((bit_mask & RTC_UIE) && !(oldbits & RTC_UIE))
+ hpet_prev_update_sec = -1;
+
if (!oldbits)
hpet_rtc_timer_init();
@@ -652,7 +655,7 @@ static void hpet_rtc_timer_reinit(void)
if (hpet_rtc_flags & RTC_PIE)
hpet_pie_count += lost_ints;
if (printk_ratelimit())
- printk(KERN_WARNING "rtc: lost %d interrupts\n",
+ printk(KERN_WARNING "hpet1: lost %d rtc interrupts\n",
lost_ints);
}
}
@@ -670,7 +673,8 @@ irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id)
if (hpet_rtc_flags & RTC_UIE &&
curr_time.tm_sec != hpet_prev_update_sec) {
- rtc_int_flag = RTC_UF;
+ if (hpet_prev_update_sec >= 0)
+ rtc_int_flag = RTC_UF;
hpet_prev_update_sec = curr_time.tm_sec;
}