On Mon, Feb 12, 2024 at 7:44 PM Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> wrote: > > Hi Everyone, > > This is an update of > > https://lore.kernel.org/linux-pm/3232442.5fSG56mABF@kreacher/ > > fixing a few bugs and renaming the new trip point flags introduced by it. > > The original description of the patch series is still applicable: > > "The purpose of this patch series is to allow thermal zone creators > to specify which properties (temperature or hysteresis) of which > trip points can be set from user space via sysfs on a per-trip basis > instead of passing writable trips masks to the thermal zone registration > function which is both cumbersome and error prone and it doesn't even > allow to request different treatment of different trip properties. > > The writable trip masks used today only affect trip temperatures (that is, if > a trip point is in a writable trips mask, its temperature can be set via > sysfs) and they only take effect if the CONFIG_THERMAL_WRITABLE_TRIPS kernel > configuration option is set, which appears to be assumed by at least some > of the drivers using writable trips masks. Some other drivers using them > simply select CONFIG_THERMAL_WRITABLE_TRIPS which pretty much defeats its > purpose (and imx even sets this option in its defconfig). > > For this reasons, patch [1/9] removes CONFIG_THERMAL_WRITABLE_TRIPS and makes > the writable trips masks always work. > > Moreover, trip hysteresis, which is not affected either by the writable trips > masks or by CONFIG_THERMAL_WRITABLE_TRIPS, can only be set via sysfs if the > .set_trip_hyst() operation is provided by the given thermal zone, but currently > this thermal zone operation is used by no one, so effectively trip hysteresis > cannot be set via sysfs at all. This is not a problem for the majority of > drivers that want trip temperatures to be set via sysfs, because they also > don't want trip hysteresis to be changed for any trips (at least as far as I > can say), but there are use cases in which it is desirable to be able to > update trip hysteresis as well as trip temperature (for example see > https://lore.kernel.org/linux-pm/20240106191502.29126-1-quic_manafm@xxxxxxxxxxx/). > Those use cases are not addressed here directly, but after this series > addressing them should be relatively straightforward. > > Namely, patch [2/9] adds flags to struct thermal_trip and defines two of them > to indicate whether or not setting the temperature or hysteresis of the given > trip via sysfs is allowed. If a writable trips mask is passed to > thermal_zone_device_register_with_trips(), is it is used to set the > "writable temperature" flag for the trips covered by it and that flag is > then consulted by the thermal sysfs code. The "writable hysteresis" trip > flag is also taken into account by the thermal sysfs code, but it is not set > automatically in any case. > > Patch [3/9] is based on the observation that the .set_trip_hyst() thermal zone > operation is never used - it simply drops that callback from struct > thermal_zone_device_ops and adjusts the code checking its presence. > > Patches [4-8/9] update drivers using writable trips masks to set the new > "writable temperature" flag directly instead and some of them are simplified > a bit as a result. After these patches, all of the callers of > thermal_zone_device_register_with_trips() pass a zero writable trips mask > to it, so patch [9/9] drops that mask from the functions argument list and > adjusts all of its callers accordingly. > > After all of the changes in this series, allowing the hysteresis value to be > set via sysfs for a given trip is a matter of setting its "writable > hysteresis" flag (and analogously for trip temperature)." By the lack of comments I gather that this series is not controversial. It unlocks further development and it should be run through linux-next for a couple of weeks before the merge window, so reviews are welcome. Thanks!
