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| author | Thomas Gleixner <tglx@linutronix.de> | 2011-02-25 22:34:23 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2011-02-26 09:45:28 +0100 |
| commit | 3a142a0672b48a853f00af61f184c7341ac9c99d (patch) | |
| tree | e84f2647dc2ae71f2e54f2256ebce87624c11d97 /kernel/time/tick-common.c | |
| parent | 493f3358cb289ccf716c5a14fa5bb52ab75943e5 (diff) | |
| download | linux-3a142a0672b48a853f00af61f184c7341ac9c99d.tar.gz linux-3a142a0672b48a853f00af61f184c7341ac9c99d.tar.bz2 linux-3a142a0672b48a853f00af61f184c7341ac9c99d.zip | |
clockevents: Prevent oneshot mode when broadcast device is periodic
When the per cpu timer is marked CLOCK_EVT_FEAT_C3STOP, then we only
can switch into oneshot mode, when the backup broadcast device
supports oneshot mode as well. Otherwise we would try to switch the
broadcast device into an unsupported mode unconditionally. This went
unnoticed so far as the current available broadcast devices support
oneshot mode. Seth unearthed this problem while debugging and working
around an hpet related BIOS wreckage.
Add the necessary check to tick_is_oneshot_available().
Reported-and-tested-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
LKML-Reference: <alpine.LFD.2.00.1102252231200.2701@localhost6.localdomain6>
Cc: stable@kernel.org # .21 ->
Diffstat (limited to 'kernel/time/tick-common.c')
| -rw-r--r-- | kernel/time/tick-common.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c index 051bc80a0c43..ed228ef6f6b8 100644 --- a/kernel/time/tick-common.c +++ b/kernel/time/tick-common.c @@ -51,7 +51,11 @@ int tick_is_oneshot_available(void) { struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev); - return dev && (dev->features & CLOCK_EVT_FEAT_ONESHOT); + if (!dev || !(dev->features & CLOCK_EVT_FEAT_ONESHOT)) + return 0; + if (!(dev->features & CLOCK_EVT_FEAT_C3STOP)) + return 1; + return tick_broadcast_oneshot_available(); } /* |