[PATCH 3.16 014/346] usb: dwc3: fix for the isoc transfer EP_BUSY flag

[Ben Hutchings]

3.16.39-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Konrad Leszczynski <konrad.leszczynski@xxxxxxxxx>

commit 9cad39fe4e4a4fe95d8ea5a7b0692b0a6e89e38b upstream.

commit f3af36511e60 ("usb: dwc3: gadget: always
enable IOC on bulk/interrupt transfers") ended up
regressing Isochronous endpoints by clearing
DWC3_EP_BUSY flag too early, which resulted in
choppy audio playback over USB.

Fix that by partially reverting original commit and
making sure that we check for isochronous endpoints.

Fixes: f3af36511e60 ("usb: dwc3: gadget: always enable IOC
		on bulk/interrupt transfers")
Signed-off-by: Konrad Leszczynski <konrad.leszczynski@xxxxxxxxx>
Signed-off-by: Rafal Redzimski <rafal.f.redzimski@xxxxxxxxx>
Signed-off-by: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/usb/dwc3/gadget.c | 4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -2016,6 +2016,10 @@ static int dwc3_cleanup_done_reqs(struct
 		return 1;
 	}
 
+	if (usb_endpoint_xfer_isoc(dep->endpoint.desc))
+		if ((event->status & DEPEVT_STATUS_IOC) &&
+				(trb->ctrl & DWC3_TRB_CTRL_IOC))
+			return 0;
 	return 1;
 }