On Wed, 18 Aug 2021 at 11:14, Viresh Kumar <viresh.kumar@xxxxxxxxxx> wrote: > > On 18-08-21, 10:29, Ulf Hansson wrote: > > Me and Dmitry discussed adding a new genpd callback for this. I agreed > > that it seems like a reasonable thing to add, if he insists. > > > > The intent was to invoke the new callback from __genpd_dev_pm_attach() > > when the device has been attached to its genpd. This allows the > > callback, to invoke clk_get_rate() and then dev_pm_opp_set_rate(), to > > update the vote according to the current state of the HW. > > I wouldn't call dev_pm_opp_set_rate() from there, since it means > configure and enable (both) for different resources, clk, regulator, > genpd, etc.. Right, good point! dev_pm_opp_set_rate() is best called from consumer drivers, as they need to be in control. > > What we need here is just configure. So something like this then: > > - genpd->get_performance_state() > -> dev_pm_opp_get_current_opp() //New API > -> dev_pm_genpd_set_performance_state(dev, current_opp->pstate); > > This can be done just once from probe() then. How would dev_pm_opp_get_current_opp() work? Do you have a suggestion? > > > I am not sure if/why that approach seemed insufficient? > > > > Another option to solve the problem, I think, is simply to patch > > drivers to let them call dev_pm_opp_set_rate() during ->probe(), this > > should synchronize the HW state too. > > Dmitry already mentioned that this will make the device start > consuming power, and he doesn't want that, else we need an explicit > disble call as well. I am sure I understand the problem. When a device is getting probed, it needs to consume power, how else can the corresponding driver successfully probe it? > > -- > viresh Kind regards Uffe
