28.11.2021 03:43, Michał Mirosław пишет: > On Fri, Nov 26, 2021 at 09:00:44PM +0300, Dmitry Osipenko wrote: >> SoC platforms often have multiple ways of how to perform system's >> power-off and restart operations. Meanwhile today's kernel is limited to >> a single option. Add combined power-off+restart handler call chain API, >> which is inspired by the restart API. The new API provides both power-off >> and restart functionality. >> >> The old pm_power_off method will be kept around till all users are >> converted to the new API. >> >> Current restart API will be replaced by the new unified API since >> new API is its superset. The restart functionality of the sys-off handler >> API is built upon the existing restart-notifier APIs. >> >> In order to ease conversion to the new API, convenient helpers are added >> for the common use-cases. They will reduce amount of boilerplate code and >> remove global variables. These helpers preserve old behaviour for cases >> where only one power-off handler is expected, this is what all existing >> drivers want, and thus, they could be easily converted to the new API. >> Users of the new API should explicitly enable power-off chaining by >> setting corresponding flag of the power_handler structure. > [...] > > Hi, > > A general question: do we really need three distinct chains for this? Hello Michał, At minimum this makes code easier to follow. > Can't there be only one that chain of callbacks that get a stage > (RESTART_PREPARE, RESTART, POWER_OFF_PREPARE, POWER_OFF) and can ignore > them at will? Calling through POWER_OFF_PREPARE would also return > whether that POWER_OFF is possible (for kernel_can_power_off()). I'm having trouble with parsing this comment. Could you please try to rephrase it? I don't see how you could check whether power-off handler is available if you'll mix all handlers together. > I would also split this patch into preparation cleanups (like wrapping > pm_power_off call with a function) and adding the notifier-based > implementation. What's the benefit of this split up will be? Are you suggesting that it will ease reviewing of this patch or something else?
