From 06a695cdefc7a435c7a045e0b759d161589d294f Mon Sep 17 00:00:00 2001 From: "Kevin Hilman (TI)" Date: Thu, 24 Sep 2026 13:29:59 -0700 Subject: [PATCH] pmdomain: core: add support system-wide resume latency constraints In addition to checking for CPU latency constraints when checking if OK to power down a domain, also check for QoS latency constraints in all devices of a domain and use that in determining the final latency constraint to use for the domain. Since cpu_system_power_down_ok() is used for system-wide suspend, the per-device constratints are only relevant if the LATENCY_SYS QoS flag is set. Reviewed-by: Abel Vesa Reviewed-by: Kendall Willis Signed-off-by: Kevin Hilman (TI) Signed-off-by: Ulf Hansson --- drivers/pmdomain/governor.c | 45 +++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) diff --git a/drivers/pmdomain/governor.c b/drivers/pmdomain/governor.c index 96737abbb496..38bba24ec26e 100644 --- a/drivers/pmdomain/governor.c +++ b/drivers/pmdomain/governor.c @@ -13,6 +13,8 @@ #include #include +#include "core.h" + static int dev_update_qos_constraint(struct device *dev, void *data) { s64 *constraint_ns_p = data; @@ -425,17 +427,60 @@ static bool cpu_power_down_ok(struct dev_pm_domain *pd) return true; } +/** + * check_device_qos_latency - Callback to check device QoS latency constraints + * @dev: Device to check + * @data: Pointer to s32 variable holding minimum latency found so far + * + * This callback checks if the device has a system-wide resume latency QoS + * constraint and updates the minimum latency if this device has a stricter + * constraint. + * + * The system-wide flag is checked first so that devices that have not opted + * in only incur a single lockless read. + * + * Returns: 0 to continue iteration. + */ +static int check_device_qos_latency(struct device *dev, void *data) +{ + s32 *min_dev_latency = data; + s32 dev_latency; + + if (!(dev_pm_qos_raw_flags(dev) & PM_QOS_FLAG_LATENCY_SYS)) + return 0; + + dev_latency = dev_pm_qos_raw_resume_latency(dev); + if (dev_latency != PM_QOS_RESUME_LATENCY_NO_CONSTRAINT) { + if (dev_latency < *min_dev_latency) + *min_dev_latency = dev_latency; + } + + return 0; +} + static bool cpu_system_power_down_ok(struct dev_pm_domain *pd) { s64 constraint_ns = cpu_wakeup_latency_qos_limit() * NSEC_PER_USEC; struct generic_pm_domain *genpd = pd_to_genpd(pd); int state_idx = genpd->state_count - 1; + s32 min_dev_latency = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT; + s64 min_dev_latency_ns; if (!(genpd->flags & GENPD_FLAG_CPU_DOMAIN)) { genpd->state_idx = state_idx; return true; } + genpd_for_each_child(genpd, check_device_qos_latency, + &min_dev_latency); + + /* If device latency < CPU wakeup latency, use it instead */ + if (min_dev_latency != PM_QOS_RESUME_LATENCY_NO_CONSTRAINT) { + min_dev_latency_ns = (s64)min_dev_latency * NSEC_PER_USEC; + if (min_dev_latency_ns < constraint_ns) + constraint_ns = min_dev_latency_ns; + } + /* Find the deepest state for the latency constraint. */ while (state_idx >= 0) { s64 latency_ns = genpd->states[state_idx].power_off_latency_ns +