1 files changed, 21 insertions, 4 deletions

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);