linux-kernel - Re: [PATCH] regulator: core: if voltage scaling fails, restore original voltage values

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Date:	Wed, 12 Dec 2012 21:00:21 +0200
From:	Felipe Balbi <balbi@...com>
To:	Robert Nelson <robertcnelson@...il.com>
CC:	Paolo Pisati <paolo.pisati@...onical.com>,
	linux-omap <linux-omap@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] regulator: core: if voltage scaling fails, restore
 original voltage values

Hi,

On Wed, Dec 12, 2012 at 12:13:35PM -0600, Robert Nelson wrote:
> On Wed, Dec 12, 2012 at 5:45 AM, Paolo Pisati
> <paolo.pisati@...onical.com> wrote:
> > Signed-off-by: Paolo Pisati <paolo.pisati@...onical.com>
> > ---
> >  drivers/regulator/core.c |   16 ++++++++++++++--
> >  1 file changed, 14 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
> > index e872c8b..c347fd0 100644
> > --- a/drivers/regulator/core.c
> > +++ b/drivers/regulator/core.c
> > @@ -2250,6 +2250,7 @@ int regulator_set_voltage(struct regulator *regulator, int min_uV, int max_uV)
> >  {
> >         struct regulator_dev *rdev = regulator->rdev;
> >         int ret = 0;
> > +       int old_min_uV, old_max_uV;
> >
> >         mutex_lock(&rdev->mutex);
> >
> > @@ -2271,18 +2272,29 @@ int regulator_set_voltage(struct regulator *regulator, int min_uV, int max_uV)
> >         ret = regulator_check_voltage(rdev, &min_uV, &max_uV);
> >         if (ret < 0)
> >                 goto out;
> > +
> > +       /* restore original values in case of error */
> > +       old_min_uV = regulator->min_uV;
> > +       old_max_uV = regulator->max_uV;
> >         regulator->min_uV = min_uV;
> >         regulator->max_uV = max_uV;
> >
> >         ret = regulator_check_consumers(rdev, &min_uV, &max_uV);
> >         if (ret < 0)
> > -               goto out;
> > +               goto out2;
> >
> >         ret = _regulator_do_set_voltage(rdev, min_uV, max_uV);
> > -
> > +       if (ret < 0)
> > +               goto out2;
> > +
> >  out:
> >         mutex_unlock(&rdev->mutex);
> >         return ret;
> > +out2:
> > +       regulator->min_uV = old_min_uV;
> > +       regulator->max_uV = old_max_uV;
> > +       mutex_unlock(&rdev->mutex);
> > +       return ret;
> >  }
> >  EXPORT_SYMBOL_GPL(regulator_set_voltage);
> >
> > --
> > 1.7.10.4
> 
> Nice! This fixes the 800Mhz lockup on bootup after a software reset we
> were seeing on the Beagle xM's with v3.7.x/v3.6.x...
> 
> Tested-by: Robert Nelson <robertcnelson@...il.com>

if this fixes a boot lockup with older kernel, I believe this deserves a
Cc: stable@...r.kernel.org.

-- 
balbi

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