On Wednesday 11 Aug 2021 at 14:43:21 (+0530), Viresh Kumar wrote: > On 11-08-21, 09:37, Quentin Perret wrote: > > On Wednesday 11 Aug 2021 at 10:48:59 (+0530), Viresh Kumar wrote: > > > I had to use the pm-opp version, since almost everyone was using that. > > > > > > On the other hand, there isn't a lot of OPP specific stuff in > > > dev_pm_opp_of_register_em(). It just uses dev_pm_opp_get_opp_count(), > > > that's all. This ended up in the OPP core, nothing else. Maybe we can > > > now move it back to the EM core and name it differently ? > > > > Well it also uses dev_pm_opp_find_freq_ceil() and > > dev_pm_opp_get_voltage(), so not sure how easy it will be to move, but > > if it is possible no objection from me. > > What uses these routines ? dev_pm_opp_of_register_em() ? I am not able > to see that at least :( Yep, it's not immediately obvious, but see how it sets the struct em_data_callback to point at _get_power() where the actual energy calculation is done. So strictly speaking _get_power() is what uses these routines, but it goes in hand with dev_pm_opp_of_register_em() so I guess the same reasoning applies. > > Right but the EM is a description of the hardware, so it seemed fair > > to assume this wouldn't change across the lifetime of the OS, similar > > to the DT which we can't reload at run-time. Yes it can be a little odd > > if you load/unload your driver module, but note that you generally can't > > load two completely different drivers on a single system. You'll just > > load the same one again and the hardware hasn't changed in the meantime, > > so the previously loaded EM will still be correct. > > Yeah, it will be the same driver but a different version of it, which > may have updated the freq table. For me the EM is attached to the > freq-table, and the freq-table is not available anymore after the > driver is gone. > > Anyway, I will leave that for you guys to decide :) IIUC Lukasz is working on something that should allow changing the EM at run-time, so hopefully it'll enable this use-case as well, but we'll see :)
