2.6.37-rc2 regression: usb network hotplug

[Patrick Schaaf]

When trying out 2.6.37-rc2 on my Dell Latitude D630 laptop, I notice a
regression, compared to plain 2.6.36, related to USB unplugging my N900
(cdc_ether network device).

The usb0 interface is configured to automatically plug into a bridge
group, if that matters.

On 2.6.36 I can unplug and replug the device properly.

Under 2.6.37-rc2, the first plugging works, the device is reachable as
desired, but after unplugging it the first time, I receive the following
message every 10 seconds:

 kernel:[  149.632104] unregister_netdevice: waiting for usb0 to become
free. Usage count = 1

The usb0 device is gone at that point. Replugging does not work.

When I reboot into the same kernel, a list of "cannot reset port"
messages is apparent in the boot logs, as appended. This disappears
after shutting down the machine.

I'll gladly try out patches that could fix this, or try out other things
to help diagnose.

best regards
  Patrick

<3>[    4.449056] usb 6-1.2: device not accepting address 3, error -71
<3>[    4.452793] hub 6-1:1.0: cannot disable port 2 (err = -71)
<3>[    4.454787] hub 6-1:1.0: cannot reset port 2 (err = -71)
<3>[    4.456787] hub 6-1:1.0: cannot reset port 2 (err = -71)
<3>[    4.458787] hub 6-1:1.0: cannot reset port 2 (err = -71)
<3>[    4.460787] hub 6-1:1.0: cannot reset port 2 (err = -71)
<3>[    4.462786] hub 6-1:1.0: cannot reset port 2 (err = -71)
<3>[    4.464491] hub 6-1:1.0: Cannot enable port 2.  Maybe the USB
cable is bad?
<3>[    4.466787] hub 6-1:1.0: cannot disable port 2 (err = -71)
<3>[    4.468785] hub 6-1:1.0: cannot reset port 2 (err = -71)
<3>[    4.470786] hub 6-1:1.0: cannot reset port 2 (err = -71)
<3>[    4.472787] hub 6-1:1.0: cannot reset port 2 (err = -71)
<3>[    4.474780] hub 6-1:1.0: cannot reset port 2 (err = -71)
<3>[    4.476784] hub 6-1:1.0: cannot reset port 2 (err = -71)
<3>[    4.478261] hub 6-1:1.0: Cannot enable port 2.  Maybe the USB
cable is bad?
<3>[    4.479773] hub 6-1:1.0: cannot disable port 2 (err = -71)
<3>[    4.481773] hub 6-1:1.0: cannot reset port 2 (err = -71)
<3>[    4.483772] hub 6-1:1.0: cannot reset port 2 (err = -71)
<3>[    4.485778] hub 6-1:1.0: cannot reset port 2 (err = -71)
<3>[    4.487787] hub 6-1:1.0: cannot reset port 2 (err = -71)
<3>[    4.489789] hub 6-1:1.0: cannot reset port 2 (err = -71)
<3>[    4.491052] hub 6-1:1.0: Cannot enable port 2.  Maybe the USB
cable is bad?
<3>[    4.492788] hub 6-1:1.0: cannot disable port 2 (err = -71)
<3>[    4.494079] hub 6-1:1.0: unable to enumerate USB device on port 2
<3>[    4.495787] hub 6-1:1.0: cannot disable port 2 (err = -71)
<3>[    4.497790] hub 6-1:1.0: hub_port_status failed (err = -71)
<6>[    4.499100] usb 6-1: USB disconnect, address 2



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