diff options
| author | Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> | 2023-01-25 12:34:18 +0100 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2023-02-13 17:15:42 +0100 |
| commit | f9901f64536c39f699e6ed228c5e64e7e7ce8708 (patch) | |
| tree | 9235f2f0f8b6d839cffc3250ab44ea5a26e0770a /drivers/cpuidle/cpuidle-psci-domain.c | |
| parent | 41204a607679ccca7eabff9f2871b969d6ef2ce3 (diff) | |
cpuidle: psci: Do not suspend topology CPUs on PREEMPT_RT
The runtime Power Management of CPU topology is not compatible with
PREEMPT_RT:
1. Core cpuidle path disables IRQs.
2. Core cpuidle calls cpuidle-psci.
3. cpuidle-psci in __psci_enter_domain_idle_state() calls
pm_runtime_put_sync_suspend() and pm_runtime_get_sync() which use
spinlocks (which are sleeping on PREEMPT_RT).
Deep sleep modes are not a priority of Realtime kernels because the
latencies might become unpredictable. On the other hand the PSCI CPU
idle power domain is a parent of other devices and power domain
controllers, thus it cannot be simply skipped (e.g. on Qualcomm SM8250).
Disable the idle callbacks in cpuidle-psci and mark the domain as
always on. This is a trade-off between making PREEMPT_RT working and
still having a proper power domain hierarchy in the system.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Adrien Thierry <athierry@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpuidle/cpuidle-psci-domain.c')
| -rw-r--r-- | drivers/cpuidle/cpuidle-psci-domain.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/drivers/cpuidle/cpuidle-psci-domain.c b/drivers/cpuidle/cpuidle-psci-domain.c index c80cf9ddabd8..6ad2954948a5 100644 --- a/drivers/cpuidle/cpuidle-psci-domain.c +++ b/drivers/cpuidle/cpuidle-psci-domain.c @@ -64,8 +64,11 @@ static int psci_pd_init(struct device_node *np, bool use_osi) pd->flags |= GENPD_FLAG_IRQ_SAFE | GENPD_FLAG_CPU_DOMAIN; - /* Allow power off when OSI has been successfully enabled. */ - if (use_osi) + /* + * Allow power off when OSI has been successfully enabled. + * PREEMPT_RT is not yet ready to enter domain idle states. + */ + if (use_osi && !IS_ENABLED(CONFIG_PREEMPT_RT)) pd->power_off = psci_pd_power_off; else pd->flags |= GENPD_FLAG_ALWAYS_ON; |