Messages in this thread |  | | | Date | Fri, 8 Oct 2010 08:27:10 -0500 | | Subject | Re: [PATCH 1/3] regulator: Add notifier event on regulator disable | | From | Jeffrey Carlyle <> |
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On Mon, Jan 4, 2010 at 12:17 PM, Mark Brown <broonie@opensource.wolfsonmicro.com> wrote: > The intended use case is for drivers which disable regulators to save > power but need to do some work to restore the hardware state when > restarting. If the supplies are not actually disabled due to board > limits or sharing with other active devices this notifier allows the > driver to avoid unneeded reinitialisation, particularly when used with > runtime PM. > > Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> > --- > drivers/regulator/core.c | 7 +++++-- > include/linux/regulator/consumer.h | 4 +++- > 2 files changed, 8 insertions(+), 3 deletions(-) > > diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c > index 686ef27..cce76a8 100644 > --- a/drivers/regulator/core.c > +++ b/drivers/regulator/core.c > @@ -1341,6 +1341,9 @@ static int _regulator_disable(struct regulator_dev *rdev) > __func__, rdev_get_name(rdev)); > return ret; > } > + > + _notifier_call_chain(rdev, REGULATOR_EVENT_DISABLE, > + NULL); > } > > /* decrease our supplies ref count and disable if required */ > @@ -1399,8 +1402,8 @@ static int _regulator_force_disable(struct regulator_dev *rdev) > return ret; > } > /* notify other consumers that power has been forced off */ > - _notifier_call_chain(rdev, REGULATOR_EVENT_FORCE_DISABLE, > - NULL); > + _notifier_call_chain(rdev, REGULATOR_EVENT_FORCE_DISABLE | > + REGULATOR_EVENT_DISABLE, NULL); > } > > /* decrease our supplies ref count and disable if required */ > diff --git a/include/linux/regulator/consumer.h b/include/linux/regulator/consumer.h > index 030d922..28c9fd0 100644 > --- a/include/linux/regulator/consumer.h > +++ b/include/linux/regulator/consumer.h > @@ -89,8 +89,9 @@ > * REGULATION_OUT Regulator output is out of regulation. > * FAIL Regulator output has failed. > * OVER_TEMP Regulator over temp. > - * FORCE_DISABLE Regulator shut down by software. > + * FORCE_DISABLE Regulator forcibly shut down by software. > * VOLTAGE_CHANGE Regulator voltage changed. > + * DISABLE Regulator was disabled. > * > * NOTE: These events can be OR'ed together when passed into handler. > */ > @@ -102,6 +103,7 @@ > #define REGULATOR_EVENT_OVER_TEMP 0x10 > #define REGULATOR_EVENT_FORCE_DISABLE 0x20 > #define REGULATOR_EVENT_VOLTAGE_CHANGE 0x40 > +#define REGULATOR_EVENT_DISABLE 0x80 > > struct regulator; > > -- > 1.6.5.7
Mark et al, sorry to drag up something from nine months ago, but I'm having a problem with this patch. I have a regulator A that sets regulator B as its supply. When I call set_supply to add B as the supply for A, regulator A gets added to the supply_list for regulator B.
When I call regulator_disable(A), I end up with a call chain like this:
regulator_disable(A) - mutex_lock(A) - _regulator_disable(A) -- _regulator_disable(B) --- _notifier_call_chain(B) ---- mutex_lock(A) Which results in dead lock since we trying to acquire the mutex lock for regulator A which we already hold.
When I call regulator_disable(A), regulator_disable grabs the mutex_lock for A. Then while inside _regulator_disable, regulator_disable(B) is called since B is the supply for A. With this patch, _regulator_disable(B) ends up calling _notifier_call_chain(B). A is in the supply_list for B, so inside the notifier loop we try to grab the mutext_lock for A again.
Am I doing something wrong in how I am setting up B as the supply for A or is this bug in the regulator core code?
Thanks, - Jeff -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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