FAILED: patch "[PATCH] PM / QoS: Fix device resume latency PM QoS" failed to apply to 4.9-stable tree
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[email protected]
maintainerThe patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
Quoted 1 line
From
0cc2b4e5a020fc7f4d1795741c116c983e9467d7Mon Sep 17 00:00:00 2001
From: "Rafael J. Wysocki" <[email protected]>
Date: Tue, 24 Oct 2017 15:20:45 +0200
Subject: [PATCH] PM / QoS: Fix device resume latency PM QoS
The special value of 0 for device resume latency PM QoS means "no restriction", but there are two problems with that.
First, device resume latency PM QoS requests with 0 as the value are always put in front of requests with positive values in the priority lists used internally by the PM QoS framework, causing 0 to be chosen as an effective constraint value. However, that 0 is then interpreted as "no restriction" effectively overriding the other requests with specific restrictions which is incorrect.
Second, the users of device resume latency PM QoS have no way to specify that *any* resume latency at all should be avoided, which is an artificial limitation in general.
To address these issues, modify device resume latency PM QoS to use S32_MAX as the "no constraint" value and 0 as the "no latency at all" one and rework its users (the cpuidle menu governor, the genpd QoS governor and the runtime PM framework) to follow these changes.
Also add a special "n/a" value to the corresponding user space I/F to allow user space to indicate that it cannot accept any resume latencies at all for the given device.
Documentation/ABI/testing/sysfs-devices-power +3 -1
@@ -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.
drivers/base/cpu.c +2 -1
@@ -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 ; }
drivers/base/power/domain_governor.c +30 -23
90 lines not on this page · raw message
drivers/base/power/qos.c +1 -1
@@ -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;
drivers/base/power/runtime.c +1 -1
@@ -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 ;
drivers/base/power/sysfs.c +21 -4
@@ -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);
drivers/cpuidle/governors/menu.c +2 -2
@@ -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 */
include/linux/pm_qos.h +3 -2
@@ -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)