Some usb devices can't be resumed correctly after power off. This
patch is to add pm qos flags request to change NO_POWER_OFF and
provide usb_device_allow_power_off() for device drivers to allow or
prohibit usb core to power off the device.
Signed-off-by: Lan Tianyu <tianyu.lan@xxxxxxxxx>
---
drivers/usb/core/hub.c | 36 ++++++++++++++++++++++++++++++++++++
drivers/usb/core/port.c | 12 ++++++++++++
include/linux/usb.h | 3 +++
3 files changed, 51 insertions(+)
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 267e9d7..7aaac720 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -189,6 +189,42 @@ static struct usb_hub *hdev_to_hub(struct usb_device *hdev)
return usb_get_intfdata(hdev->actconfig->interface[0]);
}
+/**
+ * usb_device_allow_power_off - Allow or prohibit power off device.
+ * @udev: target usb device
+ * @set: choice of allow or prohibit
+ *
+ * Clearing or setting usb port's pm qos flag PM_QOS_FLAG_NO_POWER_OFF
+ * to allow or prohibit target usb device to be power off.
+ */
+int usb_device_allow_power_off(struct usb_device *udev, bool set)
+{
+ struct usb_port *port_dev;
+ struct dev_pm_qos_request *pm_qos;
+ s32 value;
+ int ret;
+
+ if (!udev->parent)
+ return -EINVAL;
+
+ port_dev =
+ hdev_to_hub(udev->parent)->ports[udev->portnum - 1];
+ pm_qos = &port_dev->pm_qos;
+ value = pm_qos->data.flr.flags;
+
+ if (set)
+ value &= ~PM_QOS_FLAG_NO_POWER_OFF;
+ else
+ value |= PM_QOS_FLAG_NO_POWER_OFF;
+
+ pm_runtime_get_sync(&port_dev->dev);
+ ret = dev_pm_qos_update_request(pm_qos, value);
+ pm_runtime_put(&port_dev->dev);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(usb_device_allow_power_off);
+
static int usb_device_supports_lpm(struct usb_device *udev)
{
/* USB 2.1 (and greater) devices indicate LPM support through
diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c
index 5a7a833..077a494 100644
--- a/drivers/usb/core/port.c
+++ b/drivers/usb/core/port.c
@@ -49,6 +49,11 @@ static const struct attribute_group *port_dev_group[] = {
static void usb_port_device_release(struct device *dev)
{
struct usb_port *port_dev = to_usb_port(dev);
+
+ pm_runtime_get_sync(dev);
+ dev_pm_qos_remove_request(&port_dev->pm_qos);
+ pm_runtime_put(dev);
+
dev_pm_qos_hide_flags(dev);
usb_acpi_unregister_power_resources(dev);
kfree(port_dev);
@@ -116,12 +121,19 @@ int usb_hub_create_port_device(struct device *intfdev,
if (retval)
goto error_expose_pm_qos;
+ retval = dev_pm_qos_add_request(&port_dev->dev, &port_dev->pm_qos,
+ DEV_PM_QOS_FLAGS, 0);
+ if (retval)
+ goto error_add_qos_request;
+
pm_runtime_set_active(&port_dev->dev);
pm_runtime_enable(&port_dev->dev);
usb_acpi_register_power_resources(&port_dev->dev);
return 0;
+error_add_qos_request:
+ pm_runtime_put(&port_dev->dev);
error_expose_pm_qos:
device_del(&port_dev->dev);
error_register:
diff --git a/include/linux/usb.h b/include/linux/usb.h
index 8002640..aa201bd 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -21,6 +21,7 @@
#include <linux/sched.h> /* for current && schedule_timeout */
#include <linux/mutex.h> /* for struct mutex */
#include <linux/pm_runtime.h> /* for runtime PM */
+#include <linux/pm_qos.h> /* for PM Qos */
struct usb_device;
struct usb_driver;
@@ -577,6 +578,7 @@ struct usb_device {
* @child: usb device attatched to the port
* @dev: generic device interface
* @port_owner: port's owner
+ * @pm_qos: port's pm qos flags request
* @connect_type: port's connect type
* @portnum: port index num based one
* @power_on: port's power state
@@ -585,6 +587,7 @@ struct usb_port {
struct usb_device *child;
struct device dev;
struct dev_state *port_owner;
+ struct dev_pm_qos_request pm_qos;
enum usb_port_connect_type connect_type;
u8 portnum;
bool power_on;
--
1.7.10.4
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