On Thu, Jan 19, 2023 at 12:04 AM srinivas pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx> wrote: > > On Wed, 2023-01-18 at 23:14 +0100, Daniel Lezcano wrote: > > On 18/01/2023 22:16, srinivas pandruvada wrote: > > > On Wed, 2023-01-18 at 22:01 +0100, Daniel Lezcano wrote: > > > > On 18/01/2023 21:53, srinivas pandruvada wrote: > > > > > On Wed, 2023-01-18 at 21:00 +0100, Daniel Lezcano wrote: > > > > > > On 18/01/2023 20:16, srinivas pandruvada wrote: > > > > > > > > > > > > [ ... ] > > > > > > > > > > > > > > > But we'd better wait for the thermald test result from > > > > > > > > > Srinvias. > > > > > > > > > > > > > > > > A quick test show that things still work with thermald > > > > > > > > and > > > > > > > > these > > > > > > > > changes. > > > > > > > > > > > > > > But I have a question. In some devices trip point > > > > > > > temperature > > > > > > > is > > > > > > > not > > > > > > > static. When hardware changes, we get notification. For > > > > > > > example > > > > > > > INT3403_PERF_TRIP_POINT_CHANGED for INT3403 drivers. > > > > > > > Currently get_trip can get the latest changed value. But if > > > > > > > we > > > > > > > preregister, we need some mechanism to update them. > > > > > > > > > > > > When the notification INT3403_PERF_TRIP_POINT_CHANGED > > > > > > happens, we > > > > > > call > > > > > > int340x_thermal_read_trips() which in turn updates the trip > > > > > > points. > > > > > > > > > > > > > > > > Not sure how we handle concurrency here when driver can freely > > > > > update > > > > > trips while thermal core is using trips. > > > > > > > > Don't we have the same race without this patch ? The thermal core > > > > can > > > > call get_trip_temp() while there is an update, no ? > > > Yes it is. But I can add a mutex locally here to solve. > > > But not any longer. > > > > > > I think you need some thermal_zone_read_lock/unlock() in core, > > > which > > > can use rcu. Even mutex is fine as there will be no contention as > > > updates to trips will be rare. > > > > I was planning to provide a thermal_trips_update(tz, trips) and from > > there handle the locking. > > > > As the race was already existing, can we postpone this change after > > the > > generic trip points changes? > I think so. Well, what if this bug is reported by a user and a fix needs to be backported to "stable"? Are we going to backport the whole framework redesign along with it? Or is this extremely unlikely?
