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Subject[PATCH] PM / sysfs: Expose suspend resume driver flags in sysfs
Date
Currently there are 4 driver flags to control system suspend/resume
behavior: DPM_FLAG_NO_DIRECT_COMPLETE, DPM_FLAG_SMART_PREPARE,
DPM_FLAG_SMART_SUSPEND and DPM_FLAG_MAY_SKIP_RESUME. Make these flags
visible in sysfs as read-only to get a brief understanding of the
expected behavior of each device during suspend/resume, so as to
facilitate suspend/resume debugging/tuning.

For example:
/sys/devices/pci0000:00/0000:00:15.1/power/driver_flags:4
(DPM_FLAG_SMART_SUSPEND)

/sys/devices/pci0000:00/0000:00:07.3/power/driver_flags:5
(DPM_FLAG_NO_DIRECT_COMPLETE | DPM_FLAG_SMART_SUSPEND)

Acked-by: Len Brown <len.brown@intel.com>
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
---
drivers/base/power/sysfs.c | 29 ++++++++++++++++++++++++++++-
1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c
index a1474fb67db9..48313a1040a5 100644
--- a/drivers/base/power/sysfs.c
+++ b/drivers/base/power/sysfs.c
@@ -607,6 +607,13 @@ static ssize_t async_store(struct device *dev, struct device_attribute *attr,

static DEVICE_ATTR_RW(async);

+static ssize_t driver_flags_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sysfs_emit(buf, "%x\n", dev->power.driver_flags);
+}
+static DEVICE_ATTR_RO(driver_flags);
+
#endif /* CONFIG_PM_SLEEP */
#endif /* CONFIG_PM_ADVANCED_DEBUG */

@@ -691,6 +698,20 @@ static const struct attribute_group pm_qos_flags_attr_group = {
.attrs = pm_qos_flags_attrs,
};

+static struct attribute *pm_driver_flags_attrs[] = {
+#ifdef CONFIG_PM_ADVANCED_DEBUG
+#ifdef CONFIG_PM_SLEEP
+ &dev_attr_driver_flags.attr,
+#endif
+#endif
+ NULL,
+};
+
+static const struct attribute_group pm_driver_flags_attr_group = {
+ .name = power_group_name,
+ .attrs = pm_driver_flags_attrs,
+};
+
int dpm_sysfs_add(struct device *dev)
{
int rc;
@@ -719,11 +740,17 @@ int dpm_sysfs_add(struct device *dev)
if (rc)
goto err_wakeup;
}
- rc = pm_wakeup_source_sysfs_add(dev);
+ rc = sysfs_merge_group(&dev->kobj, &pm_driver_flags_attr_group);
if (rc)
goto err_latency;
+
+ rc = pm_wakeup_source_sysfs_add(dev);
+ if (rc)
+ goto err_flags;
return 0;

+ err_flags:
+ sysfs_unmerge_group(&dev->kobj, &pm_driver_flags_attr_group);
err_latency:
sysfs_unmerge_group(&dev->kobj, &pm_qos_latency_tolerance_attr_group);
err_wakeup:
--
2.17.1
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