From: Igor Kotrasinski <i.kotrasinsk@samsung.com>
Date: Tue, 15 Sep 2015 14:55:31 +0000 (+0200)
Subject: usb: gadget: dummy_hcd: fix rescan logic for transfer
X-Git-Tag: firefly_0821_release~176^2~1003^2~11^2~5
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=e42bd6a54b97e2a39b5004deac66a0fcd6ebbe75;p=firefly-linux-kernel-4.4.55.git

usb: gadget: dummy_hcd: fix rescan logic for transfer

transfer() schedules a rescan for transfers larger than
maxpacket, which is wrong for transfers that are multiples
of maxpacket.

Rewrite to fix and clarify packet multiple / remainder
transfer logic.

Signed-off-by: Igor Kotrasinski <i.kotrasinsk@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
---

diff --git a/drivers/usb/gadget/udc/dummy_hcd.c b/drivers/usb/gadget/udc/dummy_hcd.c
index 69a0b3fa4737..ab7e015e2f55 100644
--- a/drivers/usb/gadget/udc/dummy_hcd.c
+++ b/drivers/usb/gadget/udc/dummy_hcd.c
@@ -1385,12 +1385,15 @@ top:
 			if (len == 0)
 				break;
 
-			/* use an extra pass for the final short packet */
-			if (len > ep->ep.maxpacket) {
-				rescan = 1;
-				len -= (len % ep->ep.maxpacket);
+			/* send multiple of maxpacket first, then remainder */
+			if (len >= ep->ep.maxpacket) {
+				is_short = 0;
+				if (len % ep->ep.maxpacket)
+					rescan = 1;
+				len -= len % ep->ep.maxpacket;
+			} else {
+				is_short = 1;
 			}
-			is_short = (len % ep->ep.maxpacket) != 0;
 
 			len = dummy_perform_transfer(urb, req, len);