Messages in this thread | | | From | Nick Hu <> | Date | Tue, 30 Apr 2024 00:26:11 +0800 | Subject | Re: [PATCH] cpuidle: riscv-sbi: Add cluster_pm_enter()/exit() |
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On Tue, Apr 30, 2024 at 12:22 AM Nick Hu <nick.hu@sifive.com> wrote: > > Hi Ulf > > On Mon, Apr 29, 2024 at 10:32 PM Ulf Hansson <ulf.hansson@linaro.org> wrote: > > > > On Mon, 26 Feb 2024 at 07:51, Nick Hu <nick.hu@sifive.com> wrote: > > > > > > When the cpus in the same cluster are all in the idle state, the kernel > > > might put the cluster into a deeper low power state. Call the > > > cluster_pm_enter() before entering the low power state and call the > > > cluster_pm_exit() after the cluster woken up. > > > > > > Signed-off-by: Nick Hu <nick.hu@sifive.com> > > > > I was not cced this patch, but noticed that this patch got queued up > > recently. Sorry for not noticing earlier. > > > > If not too late, can you please drop/revert it? We should really move > > away from the CPU cluster notifiers. See more information below. > > > > > --- > > > drivers/cpuidle/cpuidle-riscv-sbi.c | 24 ++++++++++++++++++++++-- > > > 1 file changed, 22 insertions(+), 2 deletions(-) > > > > > > diff --git a/drivers/cpuidle/cpuidle-riscv-sbi.c b/drivers/cpuidle/cpuidle-riscv-sbi.c > > > index e8094fc92491..298dc76a00cf 100644 > > > --- a/drivers/cpuidle/cpuidle-riscv-sbi.c > > > +++ b/drivers/cpuidle/cpuidle-riscv-sbi.c > > > @@ -394,6 +394,7 @@ static int sbi_cpuidle_pd_power_off(struct generic_pm_domain *pd) > > > { > > > struct genpd_power_state *state = &pd->states[pd->state_idx]; > > > u32 *pd_state; > > > + int ret; > > > > > > if (!state->data) > > > return 0; > > > @@ -401,6 +402,10 @@ static int sbi_cpuidle_pd_power_off(struct generic_pm_domain *pd) > > > if (!sbi_cpuidle_pd_allow_domain_state) > > > return -EBUSY; > > > > > > + ret = cpu_cluster_pm_enter(); > > > + if (ret) > > > + return ret; > > > > Rather than using the CPU cluster notifiers, consumers of the genpd > > can register themselves to receive genpd on/off notifiers. > > > > In other words, none of this should be needed, right? > > > Thanks for the feedback! > Maybe I miss something, I'm wondering about a case like below: > If we have a shared L2 cache controller inside the cpu cluster power > domain and we add this controller to be a consumer of the power > domain, Shouldn't the genpd invoke the domain idle only after the > shared L2 cache controller is suspended? > Is there a way that we can put the L2 cache down while all cpus in the > same cluster are idle? > > [...] Sorry, I made some mistake in my second question. Update the question here: Is there a way that we can save the L2 cache states while all cpus in the same cluster are idle and the cluster could be powered down? > > > > Kind regards > > Uffe
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