From 7a3783efffc7bc2e702d774e47fad5b8e37e9ad1 Mon Sep 17 00:00:00 2001 From: Paul Zimmerman Date: Wed, 17 Nov 2010 16:26:50 -0800 Subject: [PATCH] xhci: Fix reset-device and configure-endpoint commands We have been having problems with the USB-IF Gold Tree tests when plugging and unplugging devices from the tree. I have seen that the reset-device and configure-endpoint commands, which are invoked from xhci_discover_or_reset_device() and xhci_configure_endpoint(), will sometimes time out. After much debugging, I determined that the commands themselves do not actually time out, but rather their completion events do not get delivered to the right place. This happens when the command ring has just wrapped around, and it's enqueue pointer is left pointing to the link TRB. xhci_discover_or_reset_device() and xhci_configure_endpoint() use the enqueue pointer directly as their command TRB pointer, without checking whether it's pointing to the link TRB. When the completion event arrives, if the command TRB is pointing to the link TRB, the check against the command ring dequeue pointer in handle_cmd_in_cmd_wait_list() fails, so the completion inside the command does not get signaled. The patch below fixes the timeout problem for me. This should be queued for the 2.6.35 and 2.6.36 stable trees. Signed-off-by: Paul Zimmerman Signed-off-by: Sarah Sharp Cc: stable@kernel.org --- drivers/usb/host/xhci.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index 06fca083..45e4a31 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -1549,6 +1549,15 @@ static int xhci_configure_endpoint(struct xhci_hcd *xhci, cmd_completion = command->completion; cmd_status = &command->status; command->command_trb = xhci->cmd_ring->enqueue; + + /* Enqueue pointer can be left pointing to the link TRB, + * we must handle that + */ + if ((command->command_trb->link.control & TRB_TYPE_BITMASK) + == TRB_TYPE(TRB_LINK)) + command->command_trb = + xhci->cmd_ring->enq_seg->next->trbs; + list_add_tail(&command->cmd_list, &virt_dev->cmd_list); } else { in_ctx = virt_dev->in_ctx; @@ -2272,6 +2281,15 @@ int xhci_discover_or_reset_device(struct usb_hcd *hcd, struct usb_device *udev) /* Attempt to submit the Reset Device command to the command ring */ spin_lock_irqsave(&xhci->lock, flags); reset_device_cmd->command_trb = xhci->cmd_ring->enqueue; + + /* Enqueue pointer can be left pointing to the link TRB, + * we must handle that + */ + if ((reset_device_cmd->command_trb->link.control & TRB_TYPE_BITMASK) + == TRB_TYPE(TRB_LINK)) + reset_device_cmd->command_trb = + xhci->cmd_ring->enq_seg->next->trbs; + list_add_tail(&reset_device_cmd->cmd_list, &virt_dev->cmd_list); ret = xhci_queue_reset_device(xhci, slot_id); if (ret) { -- 2.7.4