This is a note to let you know that I've just added the patch titled
clocksource: Install completely before selecting
to the 2.6.38-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
clocksource-install-completely-before-selecting.patch
and it can be found in the queue-2.6.38 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From e05b2efb82596905ebfe88e8612ee81dec9b6592 Mon Sep 17 00:00:00 2001
From: john stultz <[email protected]>
Date: Wed, 4 May 2011 18:16:50 -0700
Subject: clocksource: Install completely before selecting
From: john stultz <[email protected]>
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 protected]>
Signed-off-by: John Stultz <[email protected]>
Link: http://lkml.kernel.org/r/%3C1304558210.2943.24.camel%40work-vm%3E
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
kernel/time/clocksource.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -685,8 +685,8 @@ int __clocksource_register_scale(struct
/* Add clocksource to the clcoksource list */
mutex_lock(&clocksource_mutex);
clocksource_enqueue(cs);
- clocksource_select();
clocksource_enqueue_watchdog(cs);
+ clocksource_select();
mutex_unlock(&clocksource_mutex);
return 0;
}
@@ -706,8 +706,8 @@ 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;
}
Patches currently in stable-queue which might be from [email protected] are
queue-2.6.38/clocksource-install-completely-before-selecting.patch
queue-2.6.38/tick-clear-broadcast-active-bit-when-switching-to-oneshot.patch
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