path: root/arch
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authorMark Langsdorf <mark.langsdorf@amd.com>2011-11-18 16:33:06 +0100
committerThomas Gleixner <tglx@linutronix.de>2011-12-08 21:47:22 +0100
commit2ded6e6a94c98ea453a156748cb7fabaf39a76b9 (patch)
tree0e9df0ea561e9e5aa64482f41407473b9ce34b4a /arch
parent4e2b1c4f56227c742bbd2ea8e8f559567eb80c3f (diff)
x86, hpet: Immediately disable HPET timer 1 if rtc irq is masked
When HPET is operating in RTC mode, the TN_ENABLE bit on timer1 controls whether the HPET or the RTC delivers interrupts to irq8. When the system goes into suspend, the RTC driver sends a signal to the HPET driver so that the HPET releases control of irq8, allowing the RTC to wake the system from suspend. The switchover is accomplished by a write to the HPET configuration registers which currently only occurs while servicing the HPET interrupt. On some systems, I have seen the system suspend before an HPET interrupt occurs, preventing the write to the HPET configuration register and leaving the HPET in control of the irq8. As the HPET is not active during suspend, it does not generate a wake signal and RTC alarms do not work. This patch forces the HPET driver to immediately transfer control of the irq8 channel to the RTC instead of waiting until the next interrupt event. Signed-off-by: Mark Langsdorf <mark.langsdorf@amd.com> Link: http://lkml.kernel.org/r/20111118153306.GB16319@alberich.amd.com Tested-by: Andreas Herrmann <andreas.herrmann3@amd.com> Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org
Diffstat (limited to 'arch')
1 files changed, 14 insertions, 7 deletions
diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index b946a9eac7d..1bb0bf4d92c 100644
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -1049,6 +1049,14 @@ int hpet_rtc_timer_init(void)
+static void hpet_disable_rtc_channel(void)
+ unsigned long cfg;
+ cfg = hpet_readl(HPET_T1_CFG);
+ cfg &= ~HPET_TN_ENABLE;
+ hpet_writel(cfg, HPET_T1_CFG);
* The functions below are called from rtc driver.
* Return 0 if HPET is not being used.
@@ -1060,6 +1068,9 @@ int hpet_mask_rtc_irq_bit(unsigned long bit_mask)
return 0;
hpet_rtc_flags &= ~bit_mask;
+ if (unlikely(!hpet_rtc_flags))
+ hpet_disable_rtc_channel();
return 1;
@@ -1125,15 +1136,11 @@ EXPORT_SYMBOL_GPL(hpet_rtc_dropped_irq);
static void hpet_rtc_timer_reinit(void)
- unsigned int cfg, delta;
+ unsigned int delta;
int lost_ints = -1;
- if (unlikely(!hpet_rtc_flags)) {
- cfg = hpet_readl(HPET_T1_CFG);
- cfg &= ~HPET_TN_ENABLE;
- hpet_writel(cfg, HPET_T1_CFG);
- return;
- }
+ if (unlikely(!hpet_rtc_flags))
+ hpet_disable_rtc_channel();
if (!(hpet_rtc_flags & RTC_PIE) || hpet_pie_limit)
delta = hpet_default_delta;