diff options
| author | Felipe Balbi | 2016-09-29 15:44:29 +0300 |
|---|---|---|
| committer | Felipe Balbi | 2016-10-17 11:14:00 +0300 |
| commit | d889c23ce4e3159e3d737f55f9d686a030a7ba87 (patch) | |
| tree | f94ae828a487c92d7533b3d804e231eadc26afc1 | |
| parent | a9c3ca5fae6bf73770f0576eaf57d5f1305ef4b3 (diff) | |
usb: dwc3: gadget: never pre-start Isochronous endpoints
We cannot pre-start isochronous endpoints because we
rely on the micro-frame number passed via
XferNotReady command for proper Isochronous
scheduling.
Fixes: 08a36b543803 ("usb: dwc3: gadget: simplify __dwc3_gadget_ep_queue()")
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
| -rw-r--r-- | drivers/usb/dwc3/gadget.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index 3c3ced128c77..f15147f79d14 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -1073,9 +1073,17 @@ static int __dwc3_gadget_ep_queue(struct dwc3_ep *dep, struct dwc3_request *req) list_add_tail(&req->list, &dep->pending_list); - if (usb_endpoint_xfer_isoc(dep->endpoint.desc) && - dep->flags & DWC3_EP_PENDING_REQUEST) { - if (list_empty(&dep->started_list)) { + /* + * NOTICE: Isochronous endpoints should NEVER be prestarted. We must + * wait for a XferNotReady event so we will know what's the current + * (micro-)frame number. + * + * Without this trick, we are very, very likely gonna get Bus Expiry + * errors which will force us issue EndTransfer command. + */ + if (usb_endpoint_xfer_isoc(dep->endpoint.desc)) { + if ((dep->flags & DWC3_EP_PENDING_REQUEST) && + list_empty(&dep->started_list)) { dwc3_stop_active_transfer(dwc, dep->number, true); dep->flags = DWC3_EP_ENABLED; } |