On Thu, 19 Oct 2023 at 12:24, Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote: > > On Wed, 18 Oct 2023 at 10:06, Stephan Gerhold > <stephan.gerhold@xxxxxxxxxxxxxxx> wrote: > > > > The genpd core caches performance state votes from devices that are > > runtime suspended as of commit 3c5a272202c2 ("PM: domains: Improve > > runtime PM performance state handling"). They get applied once the > > device becomes active again. > > > > To attach the power domains needed by qcom-cpufreq-nvmem the OPP core > > calls genpd_dev_pm_attach_by_id(). This results in "virtual" dummy > > devices that use runtime PM only to control the enable and performance > > state for the attached power domain. > > > > However, at the moment nothing ever resumes the virtual devices created > > for qcom-cpufreq-nvmem. They remain permanently runtime suspended. This > > means that performance state votes made during cpufreq scaling get > > always cached and never applied to the hardware. > > > > Fix this by enabling the devices after attaching them and use > > dev_pm_syscore_device() to ensure the power domains also stay on when > > going to suspend. Since it supplies the CPU we can never turn it off > > from Linux. There are other mechanisms to turn it off when needed, > > usually in the RPM firmware (RPMPD) or the cpuidle path (CPR genpd). > > I believe we discussed using dev_pm_syscore_device() for the previous > version. It's not intended to be used for things like the above. > > Moreover, I was under the impression that it wasn't really needed. In > fact, I would think that this actually breaks things for system > suspend/resume, as in this case the cpr driver's genpd > ->power_on|off() callbacks are no longer getting called due this, > which means that the cpr state machine isn't going to be restored > properly. Or did I get this wrong? BTW, if you really need something like the above, the proper way to do it would instead be to call device_set_awake_path() for the device. This informs genpd that the device needs to stay powered-on during system suspend (assuming that GENPD_FLAG_ACTIVE_WAKEUP has been set for it), hence it will keep the corresponding PM domain powered-on too. [...] Kind regards Uffe