Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=1a0c009ac53de4a7664a1239936f0bc258133156
Commit: 1a0c009ac53de4a7664a1239936f0bc258133156
Parent: 4713e22ce81eb8b3353e16435362eb3d0ec95640
Author: Thomas Gleixner <[EMAIL PROTECTED]>
AuthorDate: Wed Jan 30 13:30:03 2008 +0100
Committer: Ingo Molnar <[EMAIL PROTECTED]>
CommitDate: Wed Jan 30 13:30:03 2008 +0100
x86: unregister PIT clocksource when PIT is disabled
The following scenario might leave PIT as a disfunctional clock source:
PIT is registered as clocksource
PM_TIMER is registered as clocksource and enables highres/dyntick mode
PIT is switched to oneshot mode
-> now the readout of PIT is bogus, but the user might select PIT
via the sysfs override, which would break the box as the time
readout is unusable.
Unregister the PIT clocksource when the PIT clock event device is switched
into shutdown / oneshot mode.
Signed-off-by: Thomas Gleixner <[EMAIL PROTECTED]>
Signed-off-by: Ingo Molnar <[EMAIL PROTECTED]>
---
arch/x86/kernel/i8253.c | 19 +++++++++++++++++++
1 files changed, 19 insertions(+), 0 deletions(-)
diff --git a/arch/x86/kernel/i8253.c b/arch/x86/kernel/i8253.c
index decc5d2..377c3f8 100644
--- a/arch/x86/kernel/i8253.c
+++ b/arch/x86/kernel/i8253.c
@@ -18,6 +18,12 @@
DEFINE_SPINLOCK(i8253_lock);
EXPORT_SYMBOL(i8253_lock);
+#ifdef CONFIG_X86_32
+static void pit_disable_clocksource(void);
+#else
+static inline void pit_disable_clocksource(void) { }
+#endif
+
/*
* HPET replaces the PIT, when enabled. So we need to know, which of
* the two timers is used
@@ -52,11 +58,13 @@ static void init_pit_timer(enum clock_event_mode mode,
outb_p(0, PIT_CH0);
outb_p(0, PIT_CH0);
}
+ pit_disable_clocksource();
break;
case CLOCK_EVT_MODE_ONESHOT:
/* One shot setup */
outb_p(0x38, PIT_MODE);
+ pit_disable_clocksource();
break;
case CLOCK_EVT_MODE_RESUME:
@@ -196,6 +204,17 @@ static struct clocksource clocksource_pit = {
.shift = 20,
};
+static void pit_disable_clocksource(void)
+{
+ /*
+ * Use mult to check whether it is registered or not
+ */
+ if (clocksource_pit.mult) {
+ clocksource_unregister(&clocksource_pit);
+ clocksource_pit.mult = 0;
+ }
+}
+
static int __init init_pit_clocksource(void)
{
/*
-
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