diff --git a/Documentation/ABI/testing/sysfs-devices-power b/Documentation/ABI/testing/sysfs-devices-power index 676fdf5f2a99..5cbb6f038615 100644 --- a/Documentation/ABI/testing/sysfs-devices-power +++ b/Documentation/ABI/testing/sysfs-devices-power @@ -211,7 +211,9 @@ Description: device, after it has been suspended at run time, from a resume request to the moment the device will be ready to process I/O, in microseconds. If it is equal to 0, however, this means that - the PM QoS resume latency may be arbitrary. + the PM QoS resume latency may be arbitrary and the special value + "n/a" means that user space cannot accept any resume latency at + all for the given device. Not all drivers support this attribute. If it isn't supported, it is not present. diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index 321cd7b4d817..227bac5f1191 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -377,7 +377,8 @@ int register_cpu(struct cpu *cpu, int num) per_cpu(cpu_sys_devices, num) = &cpu->dev; register_cpu_under_node(num, cpu_to_node(num)); - dev_pm_qos_expose_latency_limit(&cpu->dev, 0); + dev_pm_qos_expose_latency_limit(&cpu->dev, + PM_QOS_RESUME_LATENCY_NO_CONSTRAINT); return 0; } diff --git a/drivers/base/power/domain_governor.c b/drivers/base/power/domain_governor.c index 281f949c5ffe..51751cc8c9e6 100644 --- a/drivers/base/power/domain_governor.c +++ b/drivers/base/power/domain_governor.c @@ -14,23 +14,20 @@ static int dev_update_qos_constraint(struct device *dev, void *data) { s64 *constraint_ns_p = data; - s32 constraint_ns = -1; + s64 constraint_ns = -1; if (dev->power.subsys_data && dev->power.subsys_data->domain_data) constraint_ns = dev_gpd_data(dev)->td.effective_constraint_ns; - if (constraint_ns < 0) { + if (constraint_ns < 0) constraint_ns = dev_pm_qos_read_value(dev); - constraint_ns *= NSEC_PER_USEC; - } - if (constraint_ns == 0) + + if (constraint_ns == PM_QOS_RESUME_LATENCY_NO_CONSTRAINT) return 0; - /* - * constraint_ns cannot be negative here, because the device has been - * suspended. - */ - if (constraint_ns < *constraint_ns_p || *constraint_ns_p == 0) + constraint_ns *= NSEC_PER_USEC; + + if (constraint_ns < *constraint_ns_p || *constraint_ns_p < 0) *constraint_ns_p = constraint_ns; return 0; @@ -63,10 +60,14 @@ static bool default_suspend_ok(struct device *dev) spin_unlock_irqrestore(&dev->power.lock, flags); - if (constraint_ns < 0) + if (constraint_ns == 0) return false; - constraint_ns *= NSEC_PER_USEC; + if (constraint_ns == PM_QOS_RESUME_LATENCY_NO_CONSTRAINT) + constraint_ns = -1; + else + constraint_ns *= NSEC_PER_USEC; + /* * We can walk the children without any additional locking, because * they all have been suspended at this point and their @@ -76,14 +77,19 @@ static bool default_suspend_ok(struct device *dev) device_for_each_child(dev, &constraint_ns, dev_update_qos_constraint); - if (constraint_ns > 0) { - constraint_ns -= td->suspend_latency_ns + - td->resume_latency_ns; - if (constraint_ns == 0) - return false; + if (constraint_ns < 0) { + /* The children have no constraints. */ + td->effective_constraint_ns = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT; + td->cached_suspend_ok = true; + } else { + constraint_ns -= td->suspend_latency_ns + td->resume_latency_ns; + if (constraint_ns > 0) { + td->effective_constraint_ns = constraint_ns; + td->cached_suspend_ok = true; + } else { + td->effective_constraint_ns = 0; + } } - td->effective_constraint_ns = constraint_ns; - td->cached_suspend_ok = constraint_ns >= 0; /* * The children have been suspended already, so we don't need to take @@ -145,13 +151,14 @@ static bool __default_power_down_ok(struct dev_pm_domain *pd, td = &to_gpd_data(pdd)->td; constraint_ns = td->effective_constraint_ns; /* default_suspend_ok() need not be called before us. */ - if (constraint_ns < 0) { + if (constraint_ns < 0) constraint_ns = dev_pm_qos_read_value(pdd->dev); - constraint_ns *= NSEC_PER_USEC; - } - if (constraint_ns == 0) + + if (constraint_ns == PM_QOS_RESUME_LATENCY_NO_CONSTRAINT) continue; + constraint_ns *= NSEC_PER_USEC; + /* * constraint_ns cannot be negative here, because the device has * been suspended. diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c index 277d43a83f53..7d29286d9313 100644 --- a/drivers/base/power/qos.c +++ b/drivers/base/power/qos.c @@ -189,7 +189,7 @@ static int dev_pm_qos_constraints_allocate(struct device *dev) plist_head_init(&c->list); c->target_value = PM_QOS_RESUME_LATENCY_DEFAULT_VALUE; c->default_value = PM_QOS_RESUME_LATENCY_DEFAULT_VALUE; - c->no_constraint_value = PM_QOS_RESUME_LATENCY_DEFAULT_VALUE; + c->no_constraint_value = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT; c->type = PM_QOS_MIN; c->notifiers = n; diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c index 7bcf80fa9ada..13e015905543 100644 --- a/drivers/base/power/runtime.c +++ b/drivers/base/power/runtime.c @@ -253,7 +253,7 @@ static int rpm_check_suspend_allowed(struct device *dev) || (dev->power.request_pending && dev->power.request == RPM_REQ_RESUME)) retval = -EAGAIN; - else if (__dev_pm_qos_read_value(dev) < 0) + else if (__dev_pm_qos_read_value(dev) == 0) retval = -EPERM; else if (dev->power.runtime_status == RPM_SUSPENDED) retval = 1; diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c index 156ab57bca77..632077f05c57 100644 --- a/drivers/base/power/sysfs.c +++ b/drivers/base/power/sysfs.c @@ -218,7 +218,14 @@ static ssize_t pm_qos_resume_latency_show(struct device *dev, struct device_attribute *attr, char *buf) { - return sprintf(buf, "%d\n", dev_pm_qos_requested_resume_latency(dev)); + s32 value = dev_pm_qos_requested_resume_latency(dev); + + if (value == 0) + return sprintf(buf, "n/a\n"); + else if (value == PM_QOS_RESUME_LATENCY_NO_CONSTRAINT) + value = 0; + + return sprintf(buf, "%d\n", value); } static ssize_t pm_qos_resume_latency_store(struct device *dev, @@ -228,11 +235,21 @@ static ssize_t pm_qos_resume_latency_store(struct device *dev, s32 value; int ret; - if (kstrtos32(buf, 0, &value)) - return -EINVAL; + if (!kstrtos32(buf, 0, &value)) { + /* + * Prevent users from writing negative or "no constraint" values + * directly. + */ + if (value < 0 || value == PM_QOS_RESUME_LATENCY_NO_CONSTRAINT) + return -EINVAL; - if (value < 0) + if (value == 0) + value = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT; + } else if (!strcmp(buf, "n/a") || !strcmp(buf, "n/a\n")) { + value = 0; + } else { return -EINVAL; + } ret = dev_pm_qos_update_request(dev->power.qos->resume_latency_req, value); diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c index 48eaf2879228..aa390404e85f 100644 --- a/drivers/cpuidle/governors/menu.c +++ b/drivers/cpuidle/governors/menu.c @@ -298,8 +298,8 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev) data->needs_update = 0; } - /* resume_latency is 0 means no restriction */ - if (resume_latency && resume_latency < latency_req) + if (resume_latency < latency_req && + resume_latency != PM_QOS_RESUME_LATENCY_NO_CONSTRAINT) latency_req = resume_latency; /* Special case when user has set very strict latency requirement */ diff --git a/include/linux/pm_qos.h b/include/linux/pm_qos.h index 032b55909145..6737a8c9e8c6 100644 --- a/include/linux/pm_qos.h +++ b/include/linux/pm_qos.h @@ -27,16 +27,17 @@ enum pm_qos_flags_status { PM_QOS_FLAGS_ALL, }; -#define PM_QOS_DEFAULT_VALUE -1 +#define PM_QOS_DEFAULT_VALUE (-1) +#define PM_QOS_LATENCY_ANY S32_MAX #define PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE (2000 * USEC_PER_SEC) #define PM_QOS_NETWORK_LAT_DEFAULT_VALUE (2000 * USEC_PER_SEC) #define PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE 0 #define PM_QOS_MEMORY_BANDWIDTH_DEFAULT_VALUE 0 #define PM_QOS_RESUME_LATENCY_DEFAULT_VALUE 0 +#define PM_QOS_RESUME_LATENCY_NO_CONSTRAINT PM_QOS_LATENCY_ANY #define PM_QOS_LATENCY_TOLERANCE_DEFAULT_VALUE 0 #define PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT (-1) -#define PM_QOS_LATENCY_ANY ((s32)(~(__u32)0 >> 1)) #define PM_QOS_FLAG_NO_POWER_OFF (1 << 0) #define PM_QOS_FLAG_REMOTE_WAKEUP (1 << 1)