On Mon, Sep 11, 2017 at 05:41:32PM +0800, yinbo.zhu@xxxxxxx wrote:
> From: "yinbo.zhu" <yinbo.zhu@xxxxxxx>
Please use your "real" name in the from portion, I don't think you have
a "." in your name, right? :)
And what hardware is this erratum for? Please put that in the subject
line as well, as well as xhci, otherwise it is very vague.
>
> Description: This is a occasional problem where the software
No need for "Description:" in a changelog text, the whole thing is a
description.
> issues an End Transfer command while a USB transfer is in progress,
> resulting in the TxFIFO being flushed when the lower layer is waiting
> for data,causing the super speed (SS) transmit to get blocked.
> If the End Transfer command is issued on an IN endpoint to
> flush out the pending transfers when the same IN endpoint
> is doing transfers on the USB, then depending upon the timing
> of the End Transfer (and the resulting internal FIFO flush),the
> lower layer (U3PTL/U3MAC) could get stuck waiting for data
> indefinitely. This blocks the transmission path on the SS, and no
> DP/ACK/ERDY/DEVNOTIF packets can be sent from the device.
> Impact: If this issue happens and the transmission gets blocked,
> then the USB host aborts and resets/re-enumerates the device.
> This unblocks the transmitt engine and the device functions normally.
>
> Workaround: Software must wait for all existing TRBs to complete before
> issuing End transfer command.
>
> Signed-off-by: yinbo.zhu <yinbo.zhu@xxxxxxx>
> ---
> drivers/usb/host/xhci.c | 23 ++++++++++++++++-------
> 1 file changed, 16 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
> index 2d6a98c1dc12..35f7821bc8b2 100644
> --- a/drivers/usb/host/xhci.c
> +++ b/drivers/usb/host/xhci.c
> @@ -1501,13 +1501,22 @@ static int xhci_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
> ret = -ENOMEM;
> goto done;
> }
> - ep->ep_state |= EP_STOP_CMD_PENDING;
> - ep->stop_cmd_timer.expires = jiffies +
> - XHCI_STOP_EP_CMD_TIMEOUT * HZ;
> - add_timer(&ep->stop_cmd_timer);
> - xhci_queue_stop_endpoint(xhci, command, urb->dev->slot_id,
> - ep_index, 0);
> - xhci_ring_cmd_db(xhci);
> +
> + /*
> + *A-009611: Issuing an End Transfer command on an IN endpoint.
> + *when a transfer is in progress on USB blocks the transmission
> + *Workaround: Software must wait for all existing TRBs to
> + *complete before issuing End transfer command.
> + */
Please properly format your comments.
And what is the A-009611: for?
And is this really for all xhci controllers?
> + if (ep_ring->enqueue == ep_ring->dequeue) {
> + ep->ep_state |= EP_STOP_CMD_PENDING;
> + ep->stop_cmd_timer.expires = jiffies +
> + XHCI_STOP_EP_CMD_TIMEOUT * HZ;
> + add_timer(&ep->stop_cmd_timer);
> + xhci_queue_stop_endpoint(xhci, command,
> + urb->dev->slot_id, ep_index, 0);
> + xhci_ring_cmd_db(xhci);
> + }
> }
thanks,
greg k-h
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