On pon, 2014-10-13 at 06:01 +0000, MyungJoo Ham wrote:
> >
> > Add a 'no_thermal' property to the power supply class. If true then
> > thermal zone won't be created for this power supply in
> > power_supply_register().
> >
> > Power supply drivers may want to set it if they support
> > POWER_SUPPLY_PROP_TEMP and they are forwarding this get property call to
> > other thermal zone.
> >
> > If they won't set it lockdep may report false positive deadlock for
> > thermal zone's mutex because of nested calls to thermal_zone_get_temp().
> > First is the call to thermal_zone_get_temp() of the driver's thermal
> > zone. Thermal core gets POWER_SUPPLY_PROP_TEMP property from this
> > driver. The driver then calls other thermal zone thermal_zone_get_temp()
> > and returns result.
> >
> > Example of such driver is charger manager.
> >
> > Signed-off-by: Krzysztof Kozlowski <[email protected]>
>
> Do we really need to add another variable in the psy struct?
> In the previous thread, I thought that wasn't needed, though.
I considered the idea mentioned by Jonghwa Lee:
static int psy_register_thermal(struct power_supply *psy)
{
...
+ if (psy->tzd)
+ return 0;
but there would be problem in determining the ownership of the thermal
zone - who should unregister that thermal zone? Charger manager's power
supply or fuel gauge's power supply?
We could NULL-ify it manually from charger's remove function before
calling power_supply_unregister... but it is really accessing a private
field of power_supply structure.
I think this should be done in API-level.
Best regards,
Krzysztof
>
>
> Cheers,
> MyungJoo
>
> >
> > ---
> >
> > Changes since v1:
> > 1. New patch (new idea).
> > ---
> > drivers/power/power_supply_core.c | 3 +++
> > include/linux/power_supply.h | 6 ++++++
> > 2 files changed, 9 insertions(+)
> >
> > diff --git a/drivers/power/power_supply_core.c
> > b/drivers/power/power_supply_core.c
> > index 6cb7fe5c022d..694e8cddd5c1 100644
> > --- a/drivers/power/power_supply_core.c
> > +++ b/drivers/power/power_supply_core.c
> > @@ -417,6 +417,9 @@ static int psy_register_thermal(struct power_supply
> > *psy)
> > {
> > int i;
> >
> > + if (psy->no_thermal)
> > + return 0;
> > +
> > /* Register battery zone device psy reports temperature */
> > for (i = 0; i < psy->num_properties; i++) {
> > if (psy->properties[i] == POWER_SUPPLY_PROP_TEMP) {
> > diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
> > index 3ed049673022..096dbced02ac 100644
> > --- a/include/linux/power_supply.h
> > +++ b/include/linux/power_supply.h
> > @@ -200,6 +200,12 @@ struct power_supply {
> > void (*external_power_changed)(struct power_supply *psy);
> > void (*set_charged)(struct power_supply *psy);
> >
> > + /*
> > + * Set if thermal zone should not be created for this power supply.
> > + * For example for virtual supplies forwarding calls to actual
> > + * sensors or other supplies.
> > + */
> > + bool no_thermal;
> > /* For APM emulation, think legacy userspace. */
> > int use_for_apm;
> >
> > --
> > 1.9.1
> >
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