* Kevin Hilman <[email protected]> [120807 11:21]:
> Jon Hunter <[email protected]> writes:
> 
> > 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]>

Thanks applying into fixes with Cc stable.

Tony
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