[3.19.y-ckt stable] Patch "usb: dwc3: gadget: don't clear EP_BUSY too early" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    usb: dwc3: gadget: don't clear EP_BUSY too early

to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue

This patch is scheduled to be released in version 3.19.y-ckt4.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

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>From dd53e3882a2c8fe1e5a2945f1c2ef6a286711437 Mon Sep 17 00:00:00 2001
From: Felipe Balbi <balbi at ti.com>
Date: Fri, 29 May 2015 10:06:38 -0500
Subject: usb: dwc3: gadget: don't clear EP_BUSY too early

commit e18b7975c885bc3a938b9a76daf32957ea0235fa upstream.

In case of non-Isochronous transfers, we don't
want to clear DWC3_EP_BUSY flag until XferComplete
event. That's because XferInProgress was only enabled
so we can recycle TRBs and usb_requests quicker, but
there are still other pending requests being transferred.

In order to make sure we don't allow for another StartTransfer
command while the HW is still processing other transfers,
we must keep DWC3_EP_BUSY flag set and this what this patch
does.

Fixes: f3af36511e60 (usb: dwc3: gadget: always enable IOC on
	bulk/interrupt transfers)
Reported-by: sundeep subbaraya <sundeep.lkml at gmail.com>
Tested-by: sundeep subbaraya <sundeep.lkml at gmail.com>
Signed-off-by: Felipe Balbi <balbi at ti.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/usb/dwc3/gadget.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 4efd3bd..5496218 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1906,12 +1906,16 @@ static void dwc3_endpoint_transfer_complete(struct dwc3 *dwc,
 {
 	unsigned		status = 0;
 	int			clean_busy;
+	u32			is_xfer_complete;
+
+	is_xfer_complete = (event->endpoint_event == DWC3_DEPEVT_XFERCOMPLETE);

 	if (event->status & DEPEVT_STATUS_BUSERR)
 		status = -ECONNRESET;

 	clean_busy = dwc3_cleanup_done_reqs(dwc, dep, event, status);
-	if (clean_busy)
+	if (clean_busy && (is_xfer_complete ||
+				usb_endpoint_xfer_isoc(dep->endpoint.desc)))
 		dep->flags &= ~DWC3_EP_BUSY;

 	/*
--
1.9.1