Initially the thermal framework had a very simple notification mechanism to send generic netlink messages to the userspace. The notification function was never called from anywhere and the corresponding dead code was removed. It was probably a first attempt to introduce the netlink notification. At LPC2018, the presentation "Linux thermal: User kernel interface", proposed to create the notifications to the userspace via a kfifo. The advantage of the kfifo is the performance. It is usually used from a 1:1 communication channel where a driver captures data and sends it as fast as possible to a userspace process. The drawback is that only one process uses the notification channel exclusively, thus no other process is allowed to use the channel to get temperature or notifications. This patch defines a generic netlink API to discover the current thermal setup and adds event notifications as well as temperature sampling. As any genetlink protocol, it can evolve and the versioning allows to keep the backward compatibility. In order to prevent the user from getting flooded with data on a single channel, there are two multicast channels, one for the temperature sampling when the thermal zone is updated and another one for the events, so the user can get the events only without the thermal zone temperature sampling. Also, a list of commands to discover the thermal setup is added and can be extended when needed.
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| @@ -37,18 +37,6 @@ struct thermal_cooling_device; · 36 unmodified lines | ||
| 37 | 37 | struct thermal_instance; |
| 38 | 38 | struct thermal_attr; |
| 39 | 39 | |
| 40 | −enum thermal_device_mode { | |
| 41 | − THERMAL_DEVICE_DISABLED = 0, | |
| 42 | − THERMAL_DEVICE_ENABLED, | |
| 43 | −}; | |
| 44 | − | |
| 45 | −enum thermal_trip_type { | |
| 46 | − THERMAL_TRIP_ACTIVE = 0, | |
| 47 | − THERMAL_TRIP_PASSIVE, | |
| 48 | − THERMAL_TRIP_HOT, | |
| 49 | − THERMAL_TRIP_CRITICAL, | |
| 50 | −}; | |
| 51 | − | |
| 52 | 40 | enum thermal_trend { |
| 53 | 41 | THERMAL_TREND_STABLE, /* temperature is stable */ |
| 54 | 42 | THERMAL_TREND_RAISING, /* temperature is raising */ |
| @@ -303,11 +291,6 @@ struct thermal_zone_params { · 248 unmodified lines | ||
| 303 | 291 | int offset; |
| 304 | 292 | }; |
| 305 | 293 | |
| 306 | −struct thermal_genl_event { | |
| 307 | − u32 orig; | |
| 308 | − enum events event; | |
| 309 | −}; | |
| 310 | − | |
| 311 | 294 | /** |
| 312 | 295 | * struct thermal_zone_of_device_ops - scallbacks for handling DT based zones |
| 313 | 296 | * |