linux-imx

USB: storage: fix Huawei mode switching regression

This reverts commit 200e0d99 ("USB: storage: optimize to match the
Huawei USB storage devices and support new switch command" and the
followup bugfix commit cd060956 ("USB: storage: properly handle
the endian issues of idProduct").

The commit effectively added a large number of Huawei devices to
the deprecated usb-storage mode switching logic.  Many of these
devices have been in use and supported by the userspace
usb_modeswitch utility for years.  Forcing the switching inside
the kernel causes a number of regressions as a result of ignoring
existing onfigurations, and also completely takes away the ability
to configure mode switching per device/system/user.

Known regressions caused by this:
 - Some of the devices support multiple modes, using different
  switching commands.  There are existing configurations taking
  advantage of this.

 - There is a real use case for disabling mode switching and
  instead mounting the exposed storage device. This becomes
  impossible with switching logic inside the usb-storage driver.

 - At least on device fail as a result of the usb-storage switching
  command, becoming completely unswitchable. This is possibly a
  firmware bug, but still a regression because the device work as
  expected using usb_modeswitch defaults.

In-kernel mode switching was deprecated years ago with the
development of the more user friendly userspace alternatives. The
existing list of devices in usb-storage was only kept to prevent
breaking already working systems.  The long term plan is to remove
the list, not to add to it. Ref:
http://permalink.gmane.org/gmane.linux.usb.general/28543

Cc: <fangxiaozhi@huawei.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>