On 16.5.2019 17.40, Jim Lin wrote:
USB 2.0 specification chapter 11.17.5 says "as part of endpoint halt processing for full-/low-speed endpoints connected via a TT, the host software must use the Clear_TT_Buffer request to the TT to ensure that the buffer is not in the busy state". In our case, a full-speed speaker (ConferenceCam) is behind a high- speed hub (ConferenceCam Connect), sometimes once we get STALL on a request we may continue to get STALL with the folllowing requests, like Set_Interface. Here we invoke usb_hub_clear_tt_buffer() to send Clear_TT_Buffer request to the hub of the device for the following Set_Interface requests to the device to get ACK successfully. Signed-off-by: Jim Lin <jilin@xxxxxxxxxx> --- v2: xhci_clear_tt_buffer_complete: add static, shorter indentation , remove its claiming in xhci.h v3: Add description for clearing_tt (xhci.h) v4: Remove clearing_tt flag because hub_tt_work has hub->tt.lock to protect for Clear_TT_Buffer to be run serially. Remove xhci_clear_tt_buffer_complete as it's not necessary. Same reason as the above. Extend usb_hub_clear_tt_buffer parameter v5: Not extending usb_hub_clear_tt_buffer parameter Add description. v6: Remove unused parameter slot_id from xhci_clear_hub_tt_buffer v7: Add devaddr field in "struct usb_device" v8: split as two patches v9: no change flag v10: Add EP_CLEARING_TT flag drivers/usb/host/xhci-ring.c | 27 ++++++++++++++++++++++++++- drivers/usb/host/xhci.c | 17 +++++++++++++++++ drivers/usb/host/xhci.h | 5 +++++ 3 files changed, 48 insertions(+), 1 deletion(-) diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index 9215a28dad40..11d498b6c09b 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -399,7 +399,7 @@ void xhci_ring_ep_doorbell(struct xhci_hcd *xhci, * stream once the endpoint is on the HW schedule. */ if ((ep_state & EP_STOP_CMD_PENDING) || (ep_state & SET_DEQ_PENDING) || - (ep_state & EP_HALTED)) + (ep_state & EP_HALTED) || (ep_state & EP_CLEARING_TT)) return; writel(DB_VALUE(ep_index, stream_id), db_addr); /* The CPU has better things to do at this point than wait for a @@ -433,6 +433,13 @@ static void ring_doorbell_for_active_rings(struct xhci_hcd *xhci, } }+void xhci_ring_doorbell_for_active_rings(struct xhci_hcd *xhci,+ unsigned int slot_id, + unsigned int ep_index) +{ + ring_doorbell_for_active_rings(xhci, slot_id, ep_index); +} + /* Get the right ring for the given slot_id, ep_index and stream_id. * If the endpoint supports streams, boundary check the URB's stream ID. * If the endpoint doesn't support streams, return the singular endpoint ring. @@ -1786,6 +1793,23 @@ struct xhci_segment *trb_in_td(struct xhci_hcd *xhci, return NULL; }+static void xhci_clear_hub_tt_buffer(struct xhci_hcd *xhci, struct xhci_td *td,+ struct xhci_virt_ep *ep) +{ + /* + * As part of low/full-speed endpoint-halt processing + * we must clear the TT buffer (USB 2.0 specification 11.17.5). + */ + if (td->urb->dev->tt && !usb_pipeint(td->urb->pipe) && + (td->urb->dev->tt->hub != xhci_to_hcd(xhci)->self.root_hub) && + !(ep->ep_state & EP_CLEARING_TT)) { + ep->ep_state |= EP_CLEARING_TT; + td->urb->ep->hcpriv = td->urb->dev; + if (usb_hub_clear_tt_buffer(td->urb)) + ep->ep_state &= ~EP_CLEARING_TT; + } +} + static void xhci_cleanup_halted_endpoint(struct xhci_hcd *xhci, unsigned int slot_id, unsigned int ep_index, unsigned int stream_id, struct xhci_td *td, @@ -1804,6 +1828,7 @@ static void xhci_cleanup_halted_endpoint(struct xhci_hcd *xhci, if (reset_type == EP_HARD_RESET) { ep->ep_state |= EP_HARD_CLEAR_TOGGLE; xhci_cleanup_stalled_ring(xhci, ep_index, stream_id, td); + xhci_clear_hub_tt_buffer(xhci, td, ep); } xhci_ring_cmd_db(xhci); } diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index 68b393e5a453..0dc108e61a89 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -5133,6 +5133,22 @@ int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks) } EXPORT_SYMBOL_GPL(xhci_gen_setup);+static void xhci_clear_tt_buffer_complete(struct usb_hcd *hcd,+ struct usb_host_endpoint *ep) +{ + struct xhci_hcd *xhci; + struct usb_device *udev; + unsigned int slot_id; + unsigned int ep_index; + + xhci = hcd_to_xhci(hcd); + udev = (struct usb_device *)ep->hcpriv; + slot_id = udev->slot_id; + ep_index = xhci_get_endpoint_index(&ep->desc);
spin_lock_irqsave(&xhci->lock, flags); (protecting ep_state)
+ xhci->devs[slot_id]->eps[ep_index].ep_state &= ~EP_CLEARING_TT; + xhci_ring_doorbell_for_active_rings(xhci, slot_id, ep_index);
unlock note: lock is already taken in xhci_cleanup_halted_endpoint() so no need to take lock for xhci_clear_hub_tt_buffer()
Other than that this looks good to me. -Mathias
