[3.16.y-ckt stable] Patch "usb: dwc3: Reset the transfer resource index on SET_INTERFACE" has been added to staging queue

[Luis Henriques]

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

    usb: dwc3: Reset the transfer resource index on SET_INTERFACE

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt16.

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

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 6ada83466be56359a7f31cbe3758957162dd6d8a Mon Sep 17 00:00:00 2001
From: John Youn <John.Youn at synopsys.com>
Date: Mon, 17 Sep 2001 00:00:00 -0700
Subject: usb: dwc3: Reset the transfer resource index on SET_INTERFACE

commit aebda618718157a69c0dc0adb978d69bc2b8723c upstream.

This fixes an issue introduced in commit b23c843992b6 (usb: dwc3:
gadget: fix DEPSTARTCFG for non-EP0 EPs) that made sure we would
only use DEPSTARTCFG once per SetConfig.

The trick is that we should use one DEPSTARTCFG per SetConfig *OR*
SetInterface. SetInterface was completely missed from the original
patch.

This problem became aparent after commit 76e838c9f776 (usb: dwc3:
gadget: return error if command sent to DEPCMD register fails)
added checking of the return status of device endpoint commands.

'Set Endpoint Transfer Resource' command was caught failing
occasionally. This is because the Transfer Resource
Index was not getting reset during a SET_INTERFACE request.

Finally, to fix the issue, was we have to do is make sure that
our start_config_issued flag gets reset whenever we receive a
SetInterface request.

To verify the problem (and its fix), all we have to do is run
test 9 from testusb with 'testusb -t 9 -s 2048 -a -c 5000'.

Tested-by: Huang Rui <ray.huang at amd.com>
Tested-by: Subbaraya Sundeep Bhatta <subbaraya.sundeep.bhatta at xilinx.com>
Fixes: b23c843992b6 (usb: dwc3: gadget: fix DEPSTARTCFG for non-EP0 EPs)
Signed-off-by: John Youn <johnyoun at synopsys.com>
Signed-off-by: Felipe Balbi <balbi at ti.com>
[ luis: backported to 3.16:
  - replaced dwc3_trace() by dev_vdbg() ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/usb/dwc3/ep0.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c
index 0985ff715c0c..bcefce032757 100644
--- a/drivers/usb/dwc3/ep0.c
+++ b/drivers/usb/dwc3/ep0.c
@@ -707,6 +707,10 @@ static int dwc3_ep0_std_request(struct dwc3 *dwc, struct usb_ctrlrequest *ctrl)
 		dev_vdbg(dwc->dev, "USB_REQ_SET_ISOCH_DELAY\n");
 		ret = dwc3_ep0_set_isoch_delay(dwc, ctrl);
 		break;
+	case USB_REQ_SET_INTERFACE:
+		dev_vdbg(dwc->dev, "USB_REQ_SET_INTERFACE");
+		dwc->start_config_issued = false;
+		/* Fall through */
 	default:
 		dev_vdbg(dwc->dev, "Forwarding to gadget driver\n");
 		ret = dwc3_ep0_delegate_req(dwc, ctrl);