[lkml]   [2011]   [May]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[19/24] clocksource: Install completely before selecting
2.6.33-longterm review patch.  If anyone has any objections, please let us know.

Content-Length: 1461
Lines: 44
From: john stultz <>

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 <>
Signed-off-by: John Stultz <>
Signed-off-by: Thomas Gleixner <>
Signed-off-by: Greg Kroah-Hartman <>

kernel/time/clocksource.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -626,8 +626,8 @@ int clocksource_register(struct clocksou

- clocksource_select();
+ clocksource_select();
return 0;

 \ /
  Last update: 2011-05-19 20:35    [from the cache]
©2003-2014 Jasper Spaans. hosted at Digital Ocean