This patch is to expose usb port's pm qos flags(pm_qos_no_power_off,
pm_qos_remote_wakeup) to user space. User can set pm_qos_no_power_off
flag to prohibit the port from being powered off.
Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Lan Tianyu <tianyu.lan@xxxxxxxxx>
---
drivers/usb/core/port.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c
index dc1aaec..0c51d24 100644
--- a/drivers/usb/core/port.c
+++ b/drivers/usb/core/port.c
@@ -67,6 +67,7 @@ static void usb_port_device_release(struct device *dev)
{
struct usb_port *port_dev = to_usb_port(dev);
+ dev_pm_qos_hide_flags(dev);
usb_acpi_unregister_power_resources(dev);
kfree(port_dev);
}
@@ -176,7 +177,15 @@ int usb_hub_create_port_device(struct usb_hub *hub, int port1)
goto error_register;
pm_runtime_set_active(&port_dev->dev);
- pm_runtime_enable(&port_dev->dev);
+
+ /* It would be dangerous if user space couldn't
+ * prevent usb device from being powered off. So don't
+ * enable port runtime pm if failed to expose port's pm qos.
+ */
+ if (!dev_pm_qos_expose_flags(&port_dev->dev,
+ PM_QOS_FLAG_NO_POWER_OFF))
+ pm_runtime_enable(&port_dev->dev);
+
usb_acpi_register_power_resources(&port_dev->dev);
return 0;
--
1.7.9.5
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