On Thu, Nov 29, 2018 at 06:46:57PM +0100, Ulf Hansson wrote: > When the hierarchical CPU topology is used and when a CPU has been put > offline (hotplug), that same CPU prevents its PM domain and thus also > potential master PM domains, from being powered off. This is because genpd > observes the CPU's struct device to remain being active from a runtime PM > point of view. > > To deal with this, let's decrease the runtime PM usage count by calling > pm_runtime_put_sync_suspend() of the CPU's struct device when putting it > offline. Consequentially, we must then increase the runtime PM usage for > the CPU, while putting it online again. > > Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx> > --- > > Changes in v10: > - Make it work when the hierarchical CPU topology is used, which may be > used both for OSI and PC mode. > - Rework the code to prevent "BUG: sleeping function called from > invalid context". > --- > drivers/firmware/psci/psci.c | 20 ++++++++++++++++++++ > 1 file changed, 20 insertions(+) > > diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c > index b03bccce0a5d..f62c4963eb62 100644 > --- a/drivers/firmware/psci/psci.c > +++ b/drivers/firmware/psci/psci.c > @@ -15,6 +15,7 @@ > > #include <linux/acpi.h> > #include <linux/arm-smccc.h> > +#include <linux/cpu.h> > #include <linux/cpuidle.h> > #include <linux/errno.h> > #include <linux/linkage.h> > @@ -199,9 +200,20 @@ static int psci_cpu_suspend(u32 state, unsigned long entry_point) > > static int psci_cpu_off(u32 state) > { > + struct device *dev; > int err; > u32 fn; > > + /* > + * When the hierarchical CPU topology is used, decrease the runtime PM > + * usage count for the current CPU, as to allow other parts in the > + * topology to enter low power states. > + */ > + if (psci_dt_topology) { > + dev = get_cpu_device(smp_processor_id()); > + pm_runtime_put_sync_suspend(dev); > + } > + > fn = psci_function_id[PSCI_FN_CPU_OFF]; > err = invoke_psci_fn(fn, state, 0, 0); > return psci_to_linux_errno(err); > @@ -209,6 +221,7 @@ static int psci_cpu_off(u32 state) > > static int psci_cpu_on(unsigned long cpuid, unsigned long entry_point) > { > + struct device *dev; > int err; > u32 fn; > > @@ -216,6 +229,13 @@ static int psci_cpu_on(unsigned long cpuid, unsigned long entry_point) > err = invoke_psci_fn(fn, cpuid, entry_point, 0); > /* Clear the domain state to start fresh. */ > psci_set_domain_state(0); > + > + /* Increase runtime PM usage count if the hierarchical CPU toplogy. */ > + if (!err && psci_dt_topology) { > + dev = get_cpu_device(cpuid); I do not like adding this code in the cpu_{on/off} method themselves, I will have a look at the patchset as whole to see how we can restructure it. More to the point, using cpuid as a logical cpu id is wrong, it is a physical id that you should convert to a logical id through get_logical_index(). Lorenzo > + pm_runtime_get_sync(dev); > + } > + > return psci_to_linux_errno(err); > } > > -- > 2.17.1 >