Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752949AbaBXIDh (ORCPT ); Mon, 24 Feb 2014 03:03:37 -0500 Received: from mx0a-0016f401.pphosted.com ([67.231.148.174]:40441 "EHLO mx0a-0016f401.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752876AbaBXIDf (ORCPT ); Mon, 24 Feb 2014 03:03:35 -0500 From: Neil Zhang To: , , , CC: Neil Zhang Subject: [PATCH 6/6] USB: gadget: mv_udc: fix corner case for missiong dTD Date: Mon, 24 Feb 2014 16:03:16 +0800 Message-ID: <1393228996-14787-7-git-send-email-zhangwm@marvell.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1393228996-14787-1-git-send-email-zhangwm@marvell.com> References: <1393228996-14787-1-git-send-email-zhangwm@marvell.com> MIME-Version: 1.0 Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:5.11.87,1.0.14,0.0.0000 definitions=2014-02-23_03:2014-02-21,2014-02-23,1970-01-01 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=7.0.1-1305240000 definitions=main-1402230265 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When the missing dTD issue is triggerred, queue_dtd may prime the new request instead of the missing dTD. We can just add the request to the queue end and jump out if there are more than one request in the queue already. Signed-off-by: Neil Zhang --- drivers/usb/gadget/mv_udc_core.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/usb/gadget/mv_udc_core.c b/drivers/usb/gadget/mv_udc_core.c index 8df8606..918b603 100644 --- a/drivers/usb/gadget/mv_udc_core.c +++ b/drivers/usb/gadget/mv_udc_core.c @@ -295,13 +295,23 @@ static int queue_dtd(struct mv_ep *ep, struct mv_req *req) /* check if the pipe is empty */ if (!(list_empty(&ep->queue))) { - struct mv_req *lastreq; + struct mv_req *firstreq, *lastreq; + firstreq = list_entry(ep->queue.next, struct mv_req, queue); lastreq = list_entry(ep->queue.prev, struct mv_req, queue); lastreq->tail->dtd_next = req->head->td_dma & EP_QUEUE_HEAD_NEXT_POINTER_MASK; wmb(); + /* + * If there are more than one reqs in the queue, + * then it's safe to just add it to the list end. + * It should be able to handle the missing DTD issue. + * And suppose it can improve the performance too. + */ + if (firstreq != lastreq) + goto done; + if (readl(&udc->op_regs->epprime) & bit_pos) goto done; -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/