The patch titled
rtc-cmos: avoid spurious irqs
has been added to the -mm tree. Its filename is
rtc-cmos-avoid-spurious-irqs.patch
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------------------------------------------------------
Subject: rtc-cmos: avoid spurious irqs
From: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxxxxxxxx>
Report-by: W Unruh <unruh@xxxxxxxxxxxxxx>
Cc: Andrew Victor <avictor.za@xxxxxxxxx>
Cc: <stable@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/hpet.c | 10 +-
drivers/rtc/rtc-cmos.c | 140 +++++++++++++++++----------------------
2 files changed, 70 insertions(+), 80 deletions(-)
diff -puN arch/x86/kernel/hpet.c~rtc-cmos-avoid-spurious-irqs arch/x86/kernel/hpet.c
--- a/arch/x86/kernel/hpet.c~rtc-cmos-avoid-spurious-irqs
+++ a/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 b
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,
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;
}
diff -puN drivers/rtc/rtc-cmos.c~rtc-cmos-avoid-spurious-irqs drivers/rtc/rtc-cmos.c
--- a/drivers/rtc/rtc-cmos.c~rtc-cmos-avoid-spurious-irqs
+++ a/drivers/rtc/rtc-cmos.c
@@ -235,11 +235,56 @@ static int cmos_read_alarm(struct device
return 0;
}
+static void cmos_checkintr(struct cmos_rtc *cmos, unsigned char rtc_control)
+{
+ unsigned char rtc_intr;
+
+ /* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
+ * allegedly some older rtcs need that to handle irqs properly
+ */
+ rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
+
+ if (is_hpet_enabled())
+ return;
+
+ rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
+ if (is_intr(rtc_intr))
+ rtc_update_irq(cmos->rtc, 1, rtc_intr);
+}
+
+static void cmos_irq_enable(struct cmos_rtc *cmos, unsigned char mask)
+{
+ unsigned char rtc_control;
+
+ /* flush any pending IRQ status, notably for update irqs,
+ * before we enable new IRQs
+ */
+ rtc_control = CMOS_READ(RTC_CONTROL);
+ cmos_checkintr(cmos, rtc_control);
+
+ rtc_control |= mask;
+ CMOS_WRITE(rtc_control, RTC_CONTROL);
+ hpet_set_rtc_irq_bit(mask);
+
+ cmos_checkintr(cmos, rtc_control);
+}
+
+static void cmos_irq_disable(struct cmos_rtc *cmos, unsigned char mask)
+{
+ unsigned char rtc_control;
+
+ rtc_control = CMOS_READ(RTC_CONTROL);
+ rtc_control &= ~mask;
+ CMOS_WRITE(rtc_control, RTC_CONTROL);
+ hpet_mask_rtc_irq_bit(mask);
+
+ cmos_checkintr(cmos, rtc_control);
+}
+
static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
{
struct cmos_rtc *cmos = dev_get_drvdata(dev);
unsigned char mon, mday, hrs, min, sec;
- unsigned char rtc_control, rtc_intr;
if (!is_valid_irq(cmos->irq))
return -EIO;
@@ -266,15 +311,7 @@ static int cmos_set_alarm(struct device
spin_lock_irq(&rtc_lock);
/* next rtc irq must not be from previous alarm setting */
- rtc_control = CMOS_READ(RTC_CONTROL);
- rtc_control &= ~RTC_AIE;
- CMOS_WRITE(rtc_control, RTC_CONTROL);
- hpet_mask_rtc_irq_bit(RTC_AIE);
-
- rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
- rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
- if (is_intr(rtc_intr))
- rtc_update_irq(cmos->rtc, 1, rtc_intr);
+ cmos_irq_disable(cmos, RTC_AIE);
/* update alarm */
CMOS_WRITE(hrs, RTC_HOURS_ALARM);
@@ -293,16 +330,8 @@ static int cmos_set_alarm(struct device
*/
hpet_set_alarm_time(t->time.tm_hour, t->time.tm_min, t->time.tm_sec);
- if (t->enabled) {
- rtc_control |= RTC_AIE;
- CMOS_WRITE(rtc_control, RTC_CONTROL);
- hpet_set_rtc_irq_bit(RTC_AIE);
-
- rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
- rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
- if (is_intr(rtc_intr))
- rtc_update_irq(cmos->rtc, 1, rtc_intr);
- }
+ if (t->enabled)
+ cmos_irq_enable(cmos, RTC_AIE);
spin_unlock_irq(&rtc_lock);
@@ -335,28 +364,17 @@ static int cmos_irq_set_freq(struct devi
static int cmos_irq_set_state(struct device *dev, int enabled)
{
struct cmos_rtc *cmos = dev_get_drvdata(dev);
- unsigned char rtc_control, rtc_intr;
unsigned long flags;
if (!is_valid_irq(cmos->irq))
return -ENXIO;
spin_lock_irqsave(&rtc_lock, flags);
- rtc_control = CMOS_READ(RTC_CONTROL);
-
- if (enabled) {
- rtc_control |= RTC_PIE;
- hpet_set_rtc_irq_bit(RTC_PIE);
- } else {
- rtc_control &= ~RTC_PIE;
- hpet_mask_rtc_irq_bit(RTC_PIE);
- }
- CMOS_WRITE(rtc_control, RTC_CONTROL);
- rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
- rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
- if (is_intr(rtc_intr))
- rtc_update_irq(cmos->rtc, 1, rtc_intr);
+ if (enabled)
+ cmos_irq_enable(cmos, RTC_PIE);
+ else
+ cmos_irq_disable(cmos, RTC_PIE);
spin_unlock_irqrestore(&rtc_lock, flags);
return 0;
@@ -368,7 +386,6 @@ static int
cmos_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
{
struct cmos_rtc *cmos = dev_get_drvdata(dev);
- unsigned char rtc_control, rtc_intr;
unsigned long flags;
switch (cmd) {
@@ -385,32 +402,20 @@ cmos_rtc_ioctl(struct device *dev, unsig
}
spin_lock_irqsave(&rtc_lock, flags);
- rtc_control = CMOS_READ(RTC_CONTROL);
switch (cmd) {
case RTC_AIE_OFF: /* alarm off */
- rtc_control &= ~RTC_AIE;
- hpet_mask_rtc_irq_bit(RTC_AIE);
+ cmos_irq_disable(cmos, RTC_AIE);
break;
case RTC_AIE_ON: /* alarm on */
- rtc_control |= RTC_AIE;
- hpet_set_rtc_irq_bit(RTC_AIE);
+ cmos_irq_enable(cmos, RTC_AIE);
break;
case RTC_UIE_OFF: /* update off */
- rtc_control &= ~RTC_UIE;
- hpet_mask_rtc_irq_bit(RTC_UIE);
+ cmos_irq_disable(cmos, RTC_UIE);
break;
case RTC_UIE_ON: /* update on */
- rtc_control |= RTC_UIE;
- hpet_set_rtc_irq_bit(RTC_UIE);
+ cmos_irq_enable(cmos, RTC_UIE);
break;
}
- CMOS_WRITE(rtc_control, RTC_CONTROL);
-
- rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
- rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
- if (is_intr(rtc_intr))
- rtc_update_irq(cmos->rtc, 1, rtc_intr);
-
spin_unlock_irqrestore(&rtc_lock, flags);
return 0;
}
@@ -571,7 +576,6 @@ static irqreturn_t cmos_interrupt(int ir
* alarm woke the system.
*/
if (irqstat & RTC_AIE) {
- rtc_control = CMOS_READ(RTC_CONTROL);
rtc_control &= ~RTC_AIE;
CMOS_WRITE(rtc_control, RTC_CONTROL);
hpet_mask_rtc_irq_bit(RTC_AIE);
@@ -685,17 +689,10 @@ cmos_do_probe(struct device *dev, struct
hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
- /* disable irqs.
- *
- * NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
- * allegedly some older rtcs need that to handle irqs properly
- */
- rtc_control = CMOS_READ(RTC_CONTROL);
- rtc_control &= ~(RTC_PIE | RTC_AIE | RTC_UIE);
- CMOS_WRITE(rtc_control, RTC_CONTROL);
- hpet_mask_rtc_irq_bit(RTC_PIE | RTC_AIE | RTC_UIE);
+ /* disable irqs */
+ cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
- CMOS_READ(RTC_INTR_FLAGS);
+ rtc_control = CMOS_READ(RTC_CONTROL);
spin_unlock_irq(&rtc_lock);
@@ -768,15 +765,8 @@ cleanup0:
static void cmos_do_shutdown(void)
{
- unsigned char rtc_control;
-
spin_lock_irq(&rtc_lock);
- rtc_control = CMOS_READ(RTC_CONTROL);
- rtc_control &= ~RTC_IRQMASK;
- CMOS_WRITE(rtc_control, RTC_CONTROL);
- hpet_mask_rtc_irq_bit(RTC_IRQMASK);
-
- CMOS_READ(RTC_INTR_FLAGS);
+ cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
spin_unlock_irq(&rtc_lock);
}
@@ -817,7 +807,6 @@ static int cmos_suspend(struct device *d
spin_lock_irq(&rtc_lock);
cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
- unsigned char irqstat;
unsigned char mask;
if (do_wake)
@@ -828,10 +817,7 @@ static int cmos_suspend(struct device *d
CMOS_WRITE(tmp, RTC_CONTROL);
hpet_mask_rtc_irq_bit(mask);
- irqstat = CMOS_READ(RTC_INTR_FLAGS);
- irqstat &= (tmp & RTC_IRQMASK) | RTC_IRQF;
- if (is_intr(irqstat))
- rtc_update_irq(cmos->rtc, 1, irqstat);
+ cmos_checkintr(cmos, tmp);
}
spin_unlock_irq(&rtc_lock);
@@ -875,7 +861,7 @@ static int cmos_resume(struct device *de
mask = CMOS_READ(RTC_INTR_FLAGS);
mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
- if (!is_intr(mask))
+ if (!is_hpet_enabled() || !is_intr(mask))
break;
/* force one-shot behavior if HPET blocked
_
Patches currently in -mm which might be from dbrownell@xxxxxxxxxxxxxxxxxxxxx are
origin.patch
gpio-pcf857x-add-lock-and-handle-more-chips.patch
linux-next.patch
add-have_clk-to-kconfig-for-driver-dependencies.patch
drivers-input-touchscreen-ads7846c-optimize-order-of-calculating-rt-in-ads7846_rx.patch
pm-boot-time-suspend-selftest.patch
pm-boot-time-suspend-selftest-vs-linux-next.patch
pm-boot-time-suspend-selftest-update.patch
drivers-power-fix-platform-driver-hotplug-coldplug.patch
mfd-fix-platform-driver-hotplug-coldplug.patch
parport-fix-platform-driver-hotplug-coldplug.patch
spi-spi_mpc83xx-clockrate-fixes.patch
xilinx_spi-test-below-0-on-unsigned-irq-in-xilinx_spi_probe.patch
spi-kconfig-simplifications.patch
spi-make-spi_board_infomodalias-a-char-array.patch
spidev-bkl-removal.patch
spi-au1550_spi-proper-platform-device.patch
spi-au1550_spi-improve-pio-transfer-mode.patch
spi-au1550_spi-improve-pio-transfer-mode-checkpatch-fixes.patch
rtc-remove-bkl-for-ioctl.patch
rtc-ds1305-ds1306-driver.patch
rtc-ds1305-ds1306-driver-fix.patch
rtc-bcd-codeshrink.patch
rtc-rtc-omap-footprint-shrinkage.patch
rtc-cmos-improve-hpet-irq-glue.patch
rtc-at91rm9200-avoid-spurious-irqs.patch
rtc-cmos-avoid-spurious-irqs.patch
gpio-gpio-driver-for-max7301-spi-gpio-expander-check-spi_setup-return-code-cleanup.patch
gpio-sysfs-interface-updated.patch
gpio-sysfs-interface-updated-update.patch
gpio-sysfs-interface-updated-gpio-linux-next-fixes-for-sysfs-support.patch
gpio-mcp23s08-handles-multiple-chips-per-chipselect.patch
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