This is a note to let you know that I've just added the patch titled
ARM: OMAP2+: Fix dmtimer set source clock failure
to the 3.5-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:
arm-omap2-fix-dmtimer-set-source-clock-failure.patch
and it can be found in the queue-3.5 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 54f32a35f4d3a653a18a2c8c239f19ae060bd803 Mon Sep 17 00:00:00 2001
From: Jon Hunter <[email protected]>
Date: Fri, 13 Jul 2012 15:12:03 -0500
Subject: ARM: OMAP2+: Fix dmtimer set source clock failure
From: Jon Hunter <[email protected]>
commit 54f32a35f4d3a653a18a2c8c239f19ae060bd803 upstream.
Calling the dmtimer function omap_dm_timer_set_source() fails if following a
call to pm_runtime_put() to disable the timer. For example the following
sequence would fail to set the parent clock ...
omap_dm_timer_stop(gptimer);
omap_dm_timer_set_source(gptimer, OMAP_TIMER_SRC_32_KHZ);
The following error message would be seen ...
omap_dm_timer_set_source: failed to set timer_32k_ck as parent
The problem is that, by design, pm_runtime_put() simply decrements the usage
count and returns before the timer has actually been disabled. Therefore,
setting the parent clock failed because the timer was still active when the
trying to set the parent clock. Setting a parent clock will fail if the clock
you are setting the parent of has a non-zero usage count. To ensure that this
does not fail use pm_runtime_put_sync() when disabling the timer.
Note that this will not be seen on OMAP1 devices, because these devices do
not use the clock framework for dmtimers.
Signed-off-by: Jon Hunter <[email protected]>
Acked-by: Kevin Hilman <[email protected]>
Signed-off-by: Tony Lindgren <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/arm/plat-omap/dmtimer.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/arm/plat-omap/dmtimer.c
+++ b/arch/arm/plat-omap/dmtimer.c
@@ -236,7 +236,7 @@ EXPORT_SYMBOL_GPL(omap_dm_timer_enable);
void omap_dm_timer_disable(struct omap_dm_timer *timer)
{
- pm_runtime_put(&timer->pdev->dev);
+ pm_runtime_put_sync(&timer->pdev->dev);
}
EXPORT_SYMBOL_GPL(omap_dm_timer_disable);
Patches currently in stable-queue which might be from [email protected] are
queue-3.5/arm-omap2-fix-dmtimer-set-source-clock-failure.patch
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