| From | Paul Gortmaker <> | Subject | [34-longterm 182/196] clocksource: Install completely before selecting | Date | Mon, 12 Mar 2012 20:21:35 -0400 |
| |
From: john stultz <johnstul@us.ibm.com>
------------------- This is a commit scheduled for the next v2.6.34 longterm release. If you see a problem with using this for longterm, please comment. -------------------
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.
[PG: 34 doesn't have __clocksource_register_scale, so drop that 1/2]
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: Paul Gortmaker <paul.gortmaker@windriver.com> --- kernel/time/clocksource.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index 1f5dde6..db24c5c 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -638,8 +638,8 @@ int clocksource_register(struct clocksource *cs) mutex_lock(&clocksource_mutex); clocksource_enqueue(cs); - clocksource_select(); clocksource_enqueue_watchdog(cs); + clocksource_select(); mutex_unlock(&clocksource_mutex); return 0; } -- 1.7.9.3
|