linux/drivers/usb/core/generic.c, branch v2.6.30

USB: Enhance usage of pm_message_t

2009-01-07T18:00:03Z

This patch (as1177) modifies the USB core suspend and resume routines. The resume functions now will take a pm_message_t argument, so they will know what sort of resume is occurring. The new argument is also passed to the port suspend/resume and bus suspend/resume routines (although they don't use it for anything but debugging). In addition, special pm_message_t values are used for user-initiated, device-initiated (i.e., remote wakeup), and automatic suspend/resume. By testing these values, drivers can tell whether or not a particular suspend was an autosuspend. Unfortunately, they can't do the same for resumes -- not until the pm_message_t argument is also passed to the drivers' resume methods. That will require a bigger change. IMO, the whole Power Management framework should have been set up this way in the first place. Signed-off-by: Alan Stern Signed-off-by: Greg Kroah-Hartman

USB: fix possible deadlock involving sysfs attributes

2008-05-29T20:59:03Z

There is a potential deadlock when the usb_generic driver is unbound from a device. The problem is that generic_disconnect() is called with the device lock held, and it removes a bunch of device attributes from sysfs. If a user task happens to be running an attribute method at the time, the removal will block until the method returns. But at least one of the attribute methods (the store routine for power/level) needs to acquire the device lock! This patch (as1093) eliminates the deadlock by moving the calls to create and remove the sysfs attributes from the usb_generic driver into usb_new_device() and usb_disconnect(), where they can be invoked without holding the device lock. Besides, the other sysfs attributes are created when the device is registered and removed when the device is unregistered. So it seems only fitting for the extra attributes to be created and removed at the same time. Signed-off-by: Alan Stern Signed-off-by: Greg Kroah-Hartman

USB: move decision to ignore FREEZE events

2007-10-12T21:55:26Z

This patch (as987) changes the way FREEZE and PRETHAW suspend events are handled in usbcore. The decision about whether or not to ignore them for non-root devices is pushed down into the USB-device driver, instead of being made in the core code. This is appropriate, since devices exported to a virtualized guest or over a network may indeed need to handle these types of suspend, even though normal devices don't. Signed-off-by: Alan Stern Signed-off-by: Greg Kroah-Hartman

USB: rename choose_configuration

2007-10-12T21:55:08Z

As it is global, give it a usb specific name in the global namespace. Cc: Inaky Perez-Gonzalez Signed-off-by: Greg Kroah-Hartman

usb: introduce usb_authorize/deauthorize()

2007-10-12T21:55:07Z

These USB API functions will do the full authorization/deauthorization to be used for a device. When authorized we effectively allow a configuration to be set. Reverse that when deauthorized. Effectively this means that we have to clean all the configuration descriptors on deauthorize and reload them when we authorized. We could do without throwing them out for wired devices, but for wireless, we can read them only after authenticating, and thus, when authorizing an authenticated device we would need to read them. So to simplify, always release them on deauthorize(), re-read them on authorize(). Also fix leak reported by Ragner Magalhaes; in usb_deauthorize_device(), bNumConfigurations was being set to zero before the for loop, and thus the different raw descriptors where never being freed. Signed-off-by: Inaky Perez-Gonzalez Signed-off-by: Greg Kroah-Hartman

usb: usb_generic_probe() obeys authorization

2007-10-12T21:55:07Z

If called and the device is not authorized to be used, then we won't choose a configuration (as they are not a concept that exists for an unauthorized device). However, the device is added to the system. Signed-off-by: Inaky Perez-Gonzalez Signed-off-by: Greg Kroah-Hartman

USB: unify reset_resume and normal resume

2007-07-12T23:34:30Z

This patch (as919) unifies the code paths used for normal resume and for reset-resume. Earlier I had failed to note a section in the USB spec which requires the host to resume a suspended port before resetting it if the attached device is enabled for remote wakeup. Since the port has to be resumed anyway, we might as well reuse the existing code. The main changes are: usb_reset_suspended_device() is eliminated. usb_root_hub_lost_power() is moved down next to the hub_reset_resume() routine, to which it is logically related. finish_port_resume() does a port reset() if the device's reset_resume flag is set. usb_port_resume() doesn't check whether the port is initially enabled if this is a USB-Persist sort of resume. Code to perform the port reset is added to the resume pathway for the non-CONFIG_USB_SUSPEND case. Signed-off-by: Alan Stern Signed-off-by: Greg Kroah-Hartman

USB: separate root and non-root suspend/resume

2007-07-12T23:34:29Z

This patch (as916) completes the separation of code paths for suspend and resume of root hubs as opposed to non-root devices. Root hubs will be power-managed through their bus_suspend and bus_resume methods, whereas normal devices will use usb_port_suspend() and usb_port_resume(). Changes to the hcd_bus_{suspend,resume} routines mostly represent motion of code that was already present elsewhere. They include: Adding debugging log messages, Setting the device state appropriately, and Adding a resume recovery time delay. Changes to the port-suspend and port-resume routines in hub.c include: Removal of checks for root devices (since they will never be triggered), and Removal of checks for NULL or invalid device pointers (these were left over from earlier kernel versions and aren't needed at all). Signed-off-by: Alan Stern Signed-off-by: Greg Kroah-Hartman

USB: add USB-Persist facility

2007-07-12T23:29:47Z

This patch (as886) adds the controversial USB-persist facility, allowing USB devices to persist across a power loss during system suspend. The facility is controlled by a new Kconfig option (with appropriate warnings about the potential dangers); when the option is off the behavior will remain the same as it is now. But when the option is on, people will be able to use suspend-to-disk and keep their USB filesystems intact -- something particularly valuable for small machines where the root filesystem is on a USB device! Signed-off-by: Alan Stern Signed-off-by: Greg Kroah-Hartman

USB: move bus_suspend and bus_resume method calls

2007-07-12T23:29:46Z

This patch (as885) moves the root-hub bus_suspend() and bus_resume() method calls from the hub driver's suspend and resume methods into the usb_generic driver methods, where they make just as much sense. Their old locations were not fully correct. For example, in a kernel compiled without CONFIG_USB_SUSPEND, if one were to do: echo -n 1-0:1.0 >/sys/bus/usb/drivers/hub/unbind to unbind the hub driver from a root hub, there would then be no way to suspend that root hub. Attempts to put the system to sleep would fail; the USB controller driver would refuse to suspend because the root hub was still active. The patch also makes a very slight change in the way devices with no driver are handled during suspend. Rather than doing a standard USB port-suspend directly, now the suspend routine in usb_generic is called. In practice this should never affect anyone. Signed-off-by: Alan Stern Signed-off-by: Greg Kroah-Hartman