Hi,
On Thu, Mar 29, 2012 at 06:16:54PM +0000, Paul Zimmerman wrote:
> Issue an Update Transfer command after queuing a request to an isoc
> EP with an active transfer. This is required according to the dwc3
> databook. Pratyush Anand reports that this fixes a problem he was
> having with Isoc IN transfers.
>
> Signed-off-by: Paul Zimmerman <paulz@xxxxxxxxxxxx>
Still waiting for a tested-by here...
> ---
> Pratyush, this is a cleaned-up version of the original patch, which
> also updates the comment in __dwc3_gadget_ep_queue() to describe
> this case. If you could, please test this version and give your
> tested-by if it works OK.
>
> drivers/usb/dwc3/gadget.c | 45 ++++++++++++++++++++++++++++-----------------
> 1 files changed, 28 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index 5255fe9..cee4e45 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -930,10 +930,12 @@ static int __dwc3_gadget_kick_transfer(struct dwc3_ep *dep, u16 cmd_param,
> }
>
> dep->flags |= DWC3_EP_BUSY;
> - dep->res_trans_idx = dwc3_gadget_ep_get_transfer_index(dwc,
> - dep->number);
>
> - WARN_ON_ONCE(!dep->res_trans_idx);
> + if (start_new) {
> + dep->res_trans_idx = dwc3_gadget_ep_get_transfer_index(dwc,
> + dep->number);
> + WARN_ON_ONCE(!dep->res_trans_idx);
> + }
>
> return 0;
> }
> @@ -967,28 +969,37 @@ static int __dwc3_gadget_ep_queue(struct dwc3_ep *dep, struct dwc3_request *req)
>
> list_add_tail(&req->list, &dep->request_list);
>
> + if (usb_endpoint_xfer_isoc(dep->desc) && (dep->flags & DWC3_EP_BUSY))
> + dep->flags |= DWC3_EP_PENDING_REQUEST;
> +
> /*
> - * There is one special case: XferNotReady with
> - * empty list of requests. We need to kick the
> - * transfer here in that situation, otherwise
> - * we will be NAKing forever.
> + * There are two special cases:
> *
> - * If we get XferNotReady before gadget driver
> - * has a chance to queue a request, we will ACK
> - * the IRQ but won't be able to receive the data
> - * until the next request is queued. The following
> - * code is handling exactly that.
> + * 1. XferNotReady with empty list of requests. We need to kick the
> + * transfer here in that situation, otherwise we will be NAKing
> + * forever. If we get XferNotReady before gadget driver has a
> + * chance to queue a request, we will ACK the IRQ but won't be
> + * able to receive the data until the next request is queued.
> + * The following code is handling exactly that.
> + *
> + * 2. XferInProgress on Isoc EP with an active transfer. We need to
> + * kick the transfer here after queuing a request, otherwise the
> + * core may not see the modified TRB(s).
> */
> if (dep->flags & DWC3_EP_PENDING_REQUEST) {
> - int ret;
> - int start_trans;
> + int ret;
> + int start_trans = 1;
> + u8 trans_idx = dep->res_trans_idx;
>
> - start_trans = 1;
> if (usb_endpoint_xfer_isoc(dep->desc) &&
> - (dep->flags & DWC3_EP_BUSY))
> + (dep->flags & DWC3_EP_BUSY)) {
> start_trans = 0;
> + WARN_ON_ONCE(!trans_idx);
> + } else {
> + trans_idx = 0;
> + }
>
> - ret = __dwc3_gadget_kick_transfer(dep, 0, start_trans);
> + ret = __dwc3_gadget_kick_transfer(dep, trans_idx, start_trans);
> if (ret && ret != -EBUSY) {
> struct dwc3 *dwc = dep->dwc;
>
> --
> Paul
>
--
balbi
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