6.15-stable review patch. If anyone has any objections, please let me know.
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From: Daniel Lezcano daniel.lezcano@linaro.org
commit 621a88dbfe9006c318a0cafbd12e677ccfe006e7 upstream.
Currently cpu hotplug with the PREEMPT_RT option set in the kernel is not supported because the underlying generic power domain functions used in the cpu hotplug callbacks are incompatible from a lock point of view. This situation prevents the suspend to idle to reach the deepest idle state for the "cluster" as identified in the undermentioned commit.
Use the compatible ones when PREEMPT_RT is enabled and remove the boolean disabling the hotplug callbacks with this option.
With this change the platform can reach the deepest idle state allowing at suspend time to consume less power.
Tested-on Lenovo T14s with the following script:
echo 0 > /sys/devices/system/cpu/cpu3/online BEFORE=$(cat /sys/kernel/debug/pm_genpd/power-domain-cpu-cluster0/idle_states | grep S0 | awk '{ print $3 }') ; rtcwake -s 1 -m mem; AFTER=$(cat /sys/kernel/debug/pm_genpd/power-domain-cpu-cluster0/idle_states | grep S0 | awk '{ print $3 }'); if [ $BEFORE -lt $AFTER ]; then echo "Test successful" else echo "Test failed" fi echo 1 > /sys/devices/system/cpu/cpu3/online
Fixes: 1c4b2932bd62 ("cpuidle: psci: Enable the hierarchical topology for s2idle on PREEMPT_RT") Cc: Raghavendra Kakarla quic_rkakarla@quicinc.com Signed-off-by: Daniel Lezcano daniel.lezcano@linaro.org Reviewed-by: Sudeep Holla sudeep.holla@arm.com Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20250709154728.733920-1-daniel.lezcano@linaro.org Signed-off-by: Ulf Hansson ulf.hansson@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/cpuidle/cpuidle-psci.c | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-)
--- a/drivers/cpuidle/cpuidle-psci.c +++ b/drivers/cpuidle/cpuidle-psci.c @@ -39,7 +39,6 @@ struct psci_cpuidle_data { static DEFINE_PER_CPU_READ_MOSTLY(struct psci_cpuidle_data, psci_cpuidle_data); static DEFINE_PER_CPU(u32, domain_state); static bool psci_cpuidle_use_syscore; -static bool psci_cpuidle_use_cpuhp;
void psci_set_domain_state(u32 state) { @@ -108,8 +107,12 @@ static int psci_idle_cpuhp_up(unsigned i { struct device *pd_dev = __this_cpu_read(psci_cpuidle_data.dev);
- if (pd_dev) - pm_runtime_get_sync(pd_dev); + if (pd_dev) { + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) + pm_runtime_get_sync(pd_dev); + else + dev_pm_genpd_resume(pd_dev); + }
return 0; } @@ -119,7 +122,11 @@ static int psci_idle_cpuhp_down(unsigned struct device *pd_dev = __this_cpu_read(psci_cpuidle_data.dev);
if (pd_dev) { - pm_runtime_put_sync(pd_dev); + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) + pm_runtime_put_sync(pd_dev); + else + dev_pm_genpd_suspend(pd_dev); + /* Clear domain state to start fresh at next online. */ psci_set_domain_state(0); } @@ -180,9 +187,6 @@ static void psci_idle_init_cpuhp(void) { int err;
- if (!psci_cpuidle_use_cpuhp) - return; - err = cpuhp_setup_state_nocalls(CPUHP_AP_CPU_PM_STARTING, "cpuidle/psci:online", psci_idle_cpuhp_up, @@ -243,10 +247,8 @@ static int psci_dt_cpu_init_topology(str * s2ram and s2idle. */ drv->states[state_count - 1].enter_s2idle = psci_enter_s2idle_domain_idle_state; - if (!IS_ENABLED(CONFIG_PREEMPT_RT)) { + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) drv->states[state_count - 1].enter = psci_enter_domain_idle_state; - psci_cpuidle_use_cpuhp = true; - }
return 0; } @@ -323,7 +325,6 @@ static void psci_cpu_deinit_idle(int cpu
dt_idle_detach_cpu(data->dev); psci_cpuidle_use_syscore = false; - psci_cpuidle_use_cpuhp = false; }
static int psci_idle_init_cpu(struct device *dev, int cpu)