From: tony@atomide•com (Tony Lindgren)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] ARM: OMAP2+: Fix dmtimer set source clock failure
Date: Tue, 7 Aug 2012 23:47:22 -0700 [thread overview]
Message-ID: <20120808064722.GB11011@atomide.com> (raw)
In-Reply-To: <87boim36mj.fsf@ti.com>
* Kevin Hilman <khilman@ti•com> [120807 11:21]:
> Jon Hunter <jon-hunter@ti•com> 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 <jon-hunter@ti•com>
>
> Acked-by: Kevin Hilman <khilman@ti•com>
Thanks applying into fixes with Cc stable.
Tony
next prev parent reply other threads:[~2012-08-08 6:47 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-13 20:12 [PATCH] ARM: OMAP2+: Fix dmtimer set source clock failure Jon Hunter
2012-08-07 7:34 ` Tony Lindgren
2012-08-07 18:21 ` Kevin Hilman
2012-08-08 6:47 ` Tony Lindgren [this message]
-- strict thread matches above, loose matches on Subject: below --
2012-07-13 20:10 Jon Hunter
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