From: Lan Tianyu Date: Tue, 22 Jan 2013 20:26:31 +0000 (+0800) Subject: usb: expose usb port's pm qos flags to user space X-Git-Tag: firefly_0821_release~3680^2~1079^2~33 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=f6cced1a08b475c5ac946823bb057714be7af4f6;p=firefly-linux-kernel-4.4.55.git usb: expose usb port's pm qos flags to user space 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 Signed-off-by: Lan Tianyu Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c index 280433d80887..9a15b26944ec 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); + retval = usb_acpi_register_power_resources(&port_dev->dev); if (retval && retval != -ENODEV)