[PATCH v2 0/7] pmdomain/cpuidle-psci: Support s2idle/s2ram on PREEMPT_RT

Ulf Hansson
2024-05-27T14:26:10Z

Updates in v2:
- Rebased and fixed a small issue in genpd, see patch3.
- Re-tested on v6.9-rt5 (PREEMPT_RT enabled)
- Re-tested on v6.10-rc1 (for regressions, PREEMPT_RT disabled)

The hierarchical PM domain topology and the corresponding domain-idle-states
are currently disabled on a PREEMPT_RT based configuration. The main reason is
because spinlocks are turned into sleepable locks on PREEMPT_RT, which means
genpd and runtime PM can't be use in the atomic idle-path when
selecting/entering an idle-state.

For s2idle/s2ram this is an unnecessary limitation that this series intends to
address. Note that, the support for cpuhotplug is left to future improvements.
More information about this are available in the commit messages.

I have tested this on a Dragonboard 410c.

Kind regards
Ulf Hansson

Ulf Hansson (7):
pmdomain: core: Enable s2idle for CPU PM domains on PREEMPT_RT
pmdomain: core: Don't hold the genpd-lock when calling
dev_pm_domain_set()
pmdomain: core: Use dev_name() instead of kobject_get_path() in
debugfs
cpuidle: psci-domain: Enable system-wide suspend on PREEMPT_RT
cpuidle: psci: Drop redundant assignment of CPUIDLE_FLAG_RCU_IDLE
cpuidle: psci: Enable the hierarchical topology for s2ram on
PREEMPT_RT
cpuidle: psci: Enable the hierarchical topology for s2idle on
PREEMPT_RT

drivers/cpuidle/cpuidle-psci-domain.c | 10 ++--
drivers/cpuidle/cpuidle-psci.c | 26 ++++++----
drivers/pmdomain/core.c | 75 +++++++++++++++++++--------
include/linux/pm_domain.h | 5 +-
4 files changed, 80 insertions(+), 36 deletions(-)

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2.34.1