Commits
Mathias Nyman committed f385e765ac9
xhci: Fix handling halted endpoint even if endpoint ring appears empty commit 93ceaa808e8defc67ebca1396e2f42f812a2efc0 upstream. If a class driver cancels its only URB then the endpoint ring buffer will appear empty to the xhci driver. xHC hardware may still process cached TRBs, and complete with a STALL, halting the endpoint. This halted endpoint was not handled correctly by xhci driver as events on empty rings were all assumed to be spurious events. xhci driver refused to restart the ring with EP_HALTED flag set, so class driver was never informed the endpoint halted even if it queued new URBs. The host side of the endpoint needs to be reset, and dequeue pointer should be moved in order to clear the cached TRBs and resetart the endpoint. Small adjustments in finding the new dequeue pointer are needed to support the case of stall on an empty ring and unknown current TD. Cc: <stable@vger.kernel.org> cc: Jeremy Compostella <jeremy.compostella@intel.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20200421140822.28233-2-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>