On 4/20/22 21:47, Rafael J. Wysocki wrote: >>>> +/** >>>> + * devm_register_prioritized_power_off_handler - Register prioritized power-off callback >>>> + * @dev: Device that registers callback >>>> + * @priority: Callback's priority >>>> + * @callback: Callback function >>>> + * @cb_data: Callback's argument >>>> + * >>>> + * Registers resource-managed power-off callback with a given priority. >>>> + * It will be called as last step of the power-off sequence. Callbacks >>>> + * chaining is disabled, i.e. further lower priority callbacks won't >>>> + * be executed if this @callback will fail to execute. >>>> + * >>>> + * Returns zero on success, or error code on failure. >>> What's the case in which this should be used instead of registering a >>> full sys_off handler? >> There are a lot of drivers that just want to register power-off handler >> with a non-default priority and don't need to stop the chain or do >> anything else special. This is a convinient helper for them. >> >> Please note that the callback here takes only the cb_data for the >> argument, while sys_off uses "struct power_off_data". >> >> Similar for the reset of the convinient helpers. > So if there is a way to do this, why would anyone prefer to use the > full sys_off handler at all? There are couple occurrences around kernel where there is no device available for the devm_ functions, like this for example [1]. [1] https://gitlab.collabora.com/dmitry.osipenko/linux-kernel-rd/-/commit/184dfd3983e774d3cf9050dc5b4ec23a662a9551 -- Best regards, Dmitry
