tched; this happens after an URB beyond
the head of the queue is unlinked.  Setting the Halt bit will then
cause the hardware to see the QH with both the Active and Halt bits
set, an invalid combination that will prevent the queue from
advancing and may even crash some controllers.

Apparently the only reason this hasn't been reported before is that
unlinking URBs from the middle of a running queue is quite uncommon.
However Test 17, recently added to the usbtest driver, does exactly
this, and it confirms the presence of the bug.

In short, there is no reason to set the Halt bit for an unlinked or
blocked QH, and there is a very good reason not to set it.  Therefore
the code that sets it is removed.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Andiry Xu <andiry.xu@amd.com>
CC: David Brownell <david-b@pacbell.net>
CC: <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
f§…