> Can we skip the new flag and just check for the correct flags here > directly? > > if (ep->ep_state & (SET_DEQ_PENDING | EP_HALTED | EP_CLEARING_TT) > break; Unfortunately not, because those pending operations may (and usually will) complete before our handler runs. They will not restart the EP because we set EP_STOP_CMD_PENDING, but they will clear their flags. So we know that Stop Endpoint is guaranteed to fail, but its handler will not see those flags and will have no clue why it failed, hence we store this one bit of knowledge specially for its use. But you raise a valid point. If Stop EP fails on a Halted endpoint and somebody else resets it before Stop EP handler runs, the handler will see EP_HALTED, because Reset EP handler must run later if the commands were queued and executed in this order. So if Stop EP handler tests for EP_HALTED, nobody needs to worry about updating EP_STOP_CMD_REDUNDANT for us. The helper function can go out, the patch is shorter, and the solution more robust against any changes to halt recovery code that anyone might do. All that "redundant" logic becomes concentrated in queue/handle _stop_endpoint() functions. I think I will do a v2. By the way, is this list of conditions complete? There are other flags like GETTING_STREAMS or CLEAR_TOGGLE, but I'm under impression that they are valid only with no queued URBs, so nothing can be cancelled then. Regards, Michal
