linux.git/drivers/usb/core/driver.c, branch v2.6.27

USB: Don't rebind before "complete" callback

2008-08-21T17:26:37+00:00

This patch (as1130) fixes an incompatibility between the new PM
infrastructure and USB power management.  We are not allowed to call
drivers' probe routines during a system sleep transition between the
"prepare" and "complete" callbacks, but that's exactly what we do when
a driver doesn't have full suspend/resume support.  Such drivers are
unbound during the "suspend" call and reprobed during the "resume" call.

The patch causes the reprobe step to be skipped if the "complete"
callback hasn't been issued yet, i.e., if the interface's
dev.power.status field is not equal to DPM_ON.  Thus during the
"resume" callback nothing bad will happen, and during the final
"complete" callback the reprobing will occur as desired.

This fixes the problem reported in Bugzilla #11263.

Signed-off-by: Alan Stern 
Signed-off-by: Greg Kroah-Hartman

USB: Add new PM callback methods for USB

2008-08-21T17:26:37+00:00

This patch (as1129) adds support for the new PM callbacks to usbcore.
The new callbacks merely invoke the same old USB power management
routines as the old ones did.

A minor improvement is that the callbacks are present only in the
"USB-device" device_type structure, rather than in the bus_type
structure.  This way they will be invoked only for USB devices, not
for USB interfaces.  The core USB PM routines automatically handle
suspending and resuming interfaces along with their devices.

Signed-off-by: Alan Stern 
Signed-off-by: Greg Kroah-Hartman

USB: Defer Set-Interface for suspended devices

2008-08-21T17:26:36+00:00

This patch (as1128) fixes one of the problems related to the new PM
infrastructure.  We are not allowed to register new child devices
during the middle of a system sleep transition, but unbinding a USB
driver causes the core to automatically install altsetting 0 and
thereby create new endpoint pseudo-devices.

The patch fixes this problem (and the related problem that installing
altsetting 0 will fail if the device is suspended) by deferring the
Set-Interface call until some later time when it is legal and can
succeed.  Possible later times are: when a new driver is being probed
for the interface, and when the interface is being resumed.

Signed-off-by: Alan Stern 
Signed-off-by: Greg Kroah-Hartman

USB: Add udev argument to interface suspend/resume functions

2008-08-21T17:26:36+00:00

This patch (as1127) makes a minor change to the prototypes of the
usb_suspend_interface() and usb_resume_interface() routines.  Now the
usb_device structure is passed as an argument, instead of being
computed on-the-fly from the usb_interface argument.

It makes the code look simpler, even if it really isn't much different
from before.

Signed-off-by: Alan Stern 
Signed-off-by: Greg Kroah-Hartman

USB: fix compiler warning fix

2008-08-14T00:32:56+00:00

This patch (as1123b) fixes a compiler warning: do_unbind_rebind() is
defined but not used if CONFIG_PM=n.

Problem originally found and initial patch submitted by Alexander
Beregalov .

Signed-off-by: Alan Stern 
Signed-off-by: Greg Kroah-Hartman

usb/core/driver: fix warning

2008-08-14T00:32:49+00:00

usb/core/driver: fix warning:
drivers/usb/core/driver.c:834: warning: 'do_unbind_rebind' defined but not used

Signed-off-by: Alexander Beregalov 
Acked-by: Alan Stern 
Signed-off-by: Greg Kroah-Hartman

USB: Force unbinding of drivers lacking reset_resume or other methods

2008-07-21T22:16:40+00:00

This patch (as1024) takes care of a FIXME issue: Drivers that don't
have the necessary suspend, resume, reset_resume, pre_reset, or
post_reset methods will be unbound and their interface reprobed when
one of the unsupported events occurs.

This is made slightly more difficult by the fact that bind operations
won't work during a system sleep transition.  So instead the code has
to defer the operation until the transition ends.

Signed-off-by: Alan Stern 
Signed-off-by: Greg Kroah-Hartman

USB: implement "soft" unbinding

2008-07-21T22:15:54+00:00

This patch (as1091) changes the way usbcore handles interface
unbinding.  If the interface's driver supports "soft" unbinding (a new
flag in the driver structure) then in-flight URBs are not cancelled
and endpoints are not disabled.  Instead the driver is allowed to
continue communicating with the device (although of course it should
stop before its disconnect routine returns).

The purpose of this change is to allow drivers to do a clean shutdown
when they get unbound from a device that is still plugged in.  Killing
all the URBs and disabling the endpoints before calling the driver's
disconnect method doesn't give the driver any control over what
happens, and it can leave devices in indeterminate states.  For
example, when usb-storage unbinds it doesn't want to stop while in the
middle of transmitting a SCSI command.

The soft_unbind flag is added because in the past, a number of drivers
have experienced problems related to ongoing I/O after their disconnect
routine returned.  Hence "soft" unbinding is made available only to
drivers that claim to support it.

The patch also replaces "interface_to_usbdev(intf)" with "udev" in a
couple of places, a minor simplification.

Signed-off-by: Alan Stern 
Signed-off-by: Greg Kroah-Hartman

USB: try to salvage lost power sessions

2008-07-21T22:15:51+00:00

This patch (as1073) adds to khubd a way to recover from power-session
interruption caused by transient connect-change or enable-change
events.  After the debouncing period, khubd attempts to do a
USB-Persist-style reset or reset-resume.  If it works, the connection
will remain unscathed.

The upshot is that we will be more immune to noise caused by EMI.  The
grace period is on the order of 100 ms, so this won't permit recovery
from the "accidentally knocked the USB cable out of its socket" type
of event, but it's a start.

As an added bonus, if a device was suspended when the system goes to
sleep then we no longer need to check for power-session interruptions
when the system wakes up.  Khubd will naturally see the status change
while processing the device's parent hub and will do the right thing.

The remote_wakeup() routine is changed; now it expects the caller to
acquire the device lock rather than acquiring the lock itself.

Signed-off-by: Alan Stern 
Signed-off-by: Greg Kroah-Hartman

USB: simplify hub_restart() logic

2008-07-21T22:15:50+00:00

This patch (as1081) straightens out the logic of the hub_restart()
routine.  Each port of the hub is scanned and the driver makes sure
that ports which are supposed to be disabled really _are_ disabled.
Any ports with a significant change in status are flagged in
hub->change_bits, so that khubd can focus on them without the need to
scan all the ports a second time -- which means the hub->activating
flag is no longer needed.

Also, it is now recognized explicitly that the only reason for
resuming a port which was not suspended is to carry out a reset-resume
operation, which happens only in a non-CONFIG_USB_SUSPEND setting.

Signed-off-by: Alan Stern 
Signed-off-by: Greg Kroah-Hartman