[PATCH] usb_interface power state
This updates the handling of power state for USB interfaces.
- Formalizes an existing invariant: interface "power state" is a boolean:
ON when I/O is allowed, and FREEZE otherwise. It does so by defining
some inlined helpers, then using them.
- Adds a useful invariant: the only interfaces marked active are those
bound to non-suspended drivers. Later patches build on this invariant.
- Simplifies the interface driver API (and removes some error paths) by
removing the requirement that they record power state changes during
suspend and resume callbacks. Now usbcore does that.
A few drivers were simplified to address that last change.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
drivers/usb/core/hub.c | 33 +++++++++------------
drivers/usb/core/message.c | 1
drivers/usb/core/usb.c | 65 +++++++++++++++++++++++++++++++++----------
drivers/usb/core/usb.h | 18 +++++++++++
drivers/usb/input/hid-core.c | 2 -
drivers/usb/misc/usbtest.c | 10 ------
drivers/usb/net/pegasus.c | 2 -
drivers/usb/net/usbnet.c | 2 -
8 files changed, 85 insertions(+), 48 deletions(-)
diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
index 4c57f3f..6ecfdce 100644
--- a/drivers/usb/core/usb.c
+++ b/drivers/usb/core/usb.c
@@ -107,10 +107,19 @@
id = usb_match_id (intf, driver->id_table);
if (id) {
dev_dbg (dev, "%s - got id\n", __FUNCTION__);
+
+ /* Interface "power state" doesn't correspond to any hardware
+ * state whatsoever. We use it to record when it's bound to
+ * a driver that may start I/0: it's not frozen/quiesced.
+ */
+ mark_active(intf);
intf->condition = USB_INTERFACE_BINDING;
error = driver->probe (intf, id);
- intf->condition = error ? USB_INTERFACE_UNBOUND :
- USB_INTERFACE_BOUND;
+ if (error) {
+ mark_quiesced(intf);
+ intf->condition = USB_INTERFACE_UNBOUND;
+ } else
+ intf->condition = USB_INTERFACE_BOUND;
}
return error;
@@ -136,6 +145,7 @@
0);
usb_set_intfdata(intf, NULL);
intf->condition = USB_INTERFACE_UNBOUND;
+ mark_quiesced(intf);
return 0;
}
@@ -299,6 +309,7 @@
dev->driver = &driver->driver;
usb_set_intfdata(iface, priv);
iface->condition = USB_INTERFACE_BOUND;
+ mark_active(iface);
/* if interface was already added, bind now; else let
* the future device_add() bind it, bypassing probe()
@@ -345,6 +356,7 @@
dev->driver = NULL;
usb_set_intfdata(iface, NULL);
iface->condition = USB_INTERFACE_UNBOUND;
+ mark_quiesced(iface);
}
/**
@@ -1404,8 +1416,9 @@
static int usb_generic_suspend(struct device *dev, pm_message_t message)
{
- struct usb_interface *intf;
- struct usb_driver *driver;
+ struct usb_interface *intf;
+ struct usb_driver *driver;
+ int status;
if (dev->driver == &usb_generic_driver)
return usb_suspend_device (to_usb_device(dev), message);
@@ -1417,21 +1430,34 @@
intf = to_usb_interface(dev);
driver = to_usb_driver(dev->driver);
- /* there's only one USB suspend state */
- if (intf->dev.power.power_state.event)
+ /* with no hardware, USB interfaces only use FREEZE and ON states */
+ if (!is_active(intf))
return 0;
- if (driver->suspend)
- return driver->suspend(intf, message);
- return 0;
+ if (driver->suspend && driver->resume) {
+ status = driver->suspend(intf, message);
+ if (status)
+ dev_err(dev, "%s error %d\n", "suspend", status);
+ else
+ mark_quiesced(intf);
+ } else {
+ // FIXME else if there's no suspend method, disconnect...
+ dev_warn(dev, "no %s?\n", "suspend");
+ status = 0;
+ }
+ return status;
}
static int usb_generic_resume(struct device *dev)
{
- struct usb_interface *intf;
- struct usb_driver *driver;
+ struct usb_interface *intf;
+ struct usb_driver *driver;
+ int status;
- /* devices resume through their hub */
+ if (dev->power.power_state.event == PM_EVENT_ON)
+ return 0;
+
+ /* devices resume through their hubs */
if (dev->driver == &usb_generic_driver)
return usb_resume_device (to_usb_device(dev));
@@ -1442,8 +1468,19 @@
intf = to_usb_interface(dev);
driver = to_usb_driver(dev->driver);
- if (driver->resume)
- return driver->resume(intf);
+ /* if driver was suspended, it has a resume method;
+ * however, sysfs can wrongly mark things as suspended
+ * (on the "no suspend method" FIXME path above)
+ */
+ mark_active(intf);
+ if (driver->resume) {
+ status = driver->resume(intf);
+ if (status) {
+ dev_err(dev, "%s error %d\n", "resume", status);
+ mark_quiesced(intf);
+ }
+ } else
+ dev_warn(dev, "no %s?\n", "resume");
return 0;
}