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.br...@intel.com> Signed-off-by: Chen Yu <yu.c.c...@intel.com> --- v2: Adding description in Documentation/ABI/testing/sysfs-devices-power according to Greg's suggestion. -- Documentation/ABI/testing/sysfs-devices-power | 11 +++++++ drivers/base/power/sysfs.c | 29 ++++++++++++++++++- 2 files changed, 39 insertions(+), 1 deletion(-) diff --git a/Documentation/ABI/testing/sysfs-devices-power b/Documentation/ABI/testing/sysfs-devices-power index 1763e64dd152..8ea68639ab3a 100644 --- a/Documentation/ABI/testing/sysfs-devices-power +++ b/Documentation/ABI/testing/sysfs-devices-power @@ -269,3 +269,14 @@ Description: the current runtime PM status of the device, which may be "suspended", "suspending", "resuming", "active", "error" (fatal error), or "unsupported" (runtime PM is disabled). + +What: /sys/devices/.../power/driver_flags +Date: October 2020 +Contact: Chen Yu <yu.c.c...@intel.com> +Description: + The /sys/devices/.../driver_flags attribute contains the driver + flags to control system suspend/resume. The flag is a combination + of DPM_FLAG_NO_DIRECT_COMPLETE, DPM_FLAG_SMART_PREPARE, + DPM_FLAG_SMART_SUSPEND and DPM_FLAG_MAY_SKIP_RESUME, or 0 if the + driver has not set any flag. This attribute is read-only. If + CONFIG_PM_ADVANCED_DEBUG is not set this attribute is empty. 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