[PATCH v12 4/4] USB / PM: Allow USB devices to remain runtime-suspended when sleeping

From: Tomeu Vizoso
Date: Thu Jan 07 2016 - 10:47:16 EST


Have dev_pm_ops.prepare return 1 for USB devices and ports so that USB
devices can remain runtime-suspended when the system goes to a sleep
state, if their wakeup state is correct and they have runtime PM enabled.

Signed-off-by: Tomeu Vizoso <tomeu.vizoso@xxxxxxxxxxxxx>
Reviewed-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
---

Changes in v10:
- Remove superfluous call to pm_runtime_enabled() as suggested by Alan

drivers/usb/core/port.c | 6 ++++++
drivers/usb/core/usb.c | 8 +++++++-
2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c
index 460c855be0d0..14718a9ffcfb 100644
--- a/drivers/usb/core/port.c
+++ b/drivers/usb/core/port.c
@@ -249,12 +249,18 @@ static int usb_port_runtime_suspend(struct device *dev)

return retval;
}
+
+static int usb_port_prepare(struct device *dev)
+{
+ return 1;
+}
#endif

static const struct dev_pm_ops usb_port_pm_ops = {
#ifdef CONFIG_PM
.runtime_suspend = usb_port_runtime_suspend,
.runtime_resume = usb_port_runtime_resume,
+ .prepare = usb_port_prepare,
#endif
};

diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
index 77e4c9bc0ab1..ebb29caa3fe4 100644
--- a/drivers/usb/core/usb.c
+++ b/drivers/usb/core/usb.c
@@ -311,7 +311,13 @@ static int usb_dev_uevent(struct device *dev, struct kobj_uevent_env *env)

static int usb_dev_prepare(struct device *dev)
{
- return 0; /* Implement eventually? */
+ struct usb_device *udev = to_usb_device(dev);
+
+ /* Return 0 if the current wakeup setting is wrong, otherwise 1 */
+ if (udev->do_remote_wakeup != device_may_wakeup(dev))
+ return 0;
+
+ return 1;
}

static void usb_dev_complete(struct device *dev)
--
2.5.0

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