USB: Disable LPM while the device is unconfigured.

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commit 9cf65991dd upstream.

The USB 3.0 Set/Clear Feature U1/U2 Enable cannot be sent to a device in
the Default or Addressed state.  It can only be sent to a configured
device.  Change the USB core to initialize the LPM disable count to 1
(disabled), which reflects this limitation.

Change usb_set_configuration() to ensure that if the device is
unconfigured on entry, usb_lpm_disable() is not called.  This avoids
sending the Clear Feature U1/U2 when the device is in the Addressed
state.  When usb_set_configuration() exits with a successfully installed
configuration, usb_lpm_enable() will be called.

Once the new configuration is installed, make sure
usb_set_configuration() only calls usb_enable_lpm() if the device moved
to the Configured state.  If we have unconfigured the device by sending
it a Set Configuration for config 0, don't enable LPM.

This commit should be backported to kernels as old as 3.5, that contain
the commit 8306095fd2 "USB: Disable USB
3.0 LPM in critical sections."

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

This commit is contained in:

Sarah Sharp 2012-07-03 23:22:38 -07:00 • committed by Greg Kroah-Hartman

parent 4d86eca285

commit 9d8d9322bf

2 changed files with 5 additions and 3 deletions

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7

drivers/usb/core/message.c

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1

drivers/usb/core/usb.c

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