Messages in this thread Patch in this message | | | Date | Thu, 19 May 2011 11:23:45 -0700 | From | Greg KH <> | Subject | [15/21] clocksource: Install completely before selecting |
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2.6.32-longterm review patch. If anyone has any objections, please let us know.
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From: john stultz <johnstul@us.ibm.com>
commit e05b2efb82596905ebfe88e8612ee81dec9b6592 upstream.
Christian Hoffmann reported that the command line clocksource override with acpi_pm timer fails:
Kernel command line: <SNIP> clocksource=acpi_pm hpet clockevent registered Switching to clocksource hpet Override clocksource acpi_pm is not HRT compatible. Cannot switch while in HRT/NOHZ mode.
The watchdog code is what enables CLOCK_SOURCE_VALID_FOR_HRES, but we actually end up selecting the clocksource before we enqueue it into the watchdog list, so that's why we see the warning and fail to switch to acpi_pm timer as requested. That's particularly bad when we want to debug timekeeping related problems in early boot.
Put the selection call last.
Reported-by: Christian Hoffmann <email@christianhoffmann.info> Signed-off-by: John Stultz <johnstul@us.ibm.com> Link: http://lkml.kernel.org/r/%3C1304558210.2943.24.camel%40work-vm%3E Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- kernel/time/clocksource.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -561,8 +561,8 @@ int clocksource_register(struct clocksou mutex_lock(&clocksource_mutex); clocksource_enqueue(cs); - clocksource_select(); clocksource_enqueue_watchdog(cs); + clocksource_select(); mutex_unlock(&clocksource_mutex); return 0; }
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