Warning at kernel/mutex.c

[u.kleine-koenig@pengutronix.de (Uwe Kleine-König)]

On Wed, Oct 19, 2011 at 08:46:03AM +0200, Sascha Hauer wrote:
> On Tue, Oct 18, 2011 at 04:45:51PM -0200, Fabio Estevam wrote:
> > 2011/10/18 Uwe Kleine-K?nig <u.kleine-koenig@pengutronix.de>:
> > 
> > >> ?static LIST_HEAD(clocks);
> > >> ?static DEFINE_MUTEX(clocks_mutex);
> > >> +static DEFINE_SPINLOCK(clock_lock);
> > > If clocks_mutex is unused now, please remove it. If it's not unused you
> > > probably introduced a problem with your patch.
> > 
> > clocks_mutex is still used in clk_set_rate and clk_set_parent.
> > 
> > Should it be converted to spinlocks too?
> >
> 
> The mutex currently used protects two things: The clock tree and the
> clock registers. If we use a mutex for the parent/rate functions and
> a spinlock for enable/disable we must make sure that both function sets
> do not access the same registers.
... and that no strage things happen when there we're in the middle of a
parent/rate change and a clock is enabled or disabled.

Best regards
Uwe

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