From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C5817C43331 for ; Mon, 30 Mar 2020 08:25:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A54FB206CC for ; Mon, 30 Mar 2020 08:25:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729630AbgC3IZ5 (ORCPT ); Mon, 30 Mar 2020 04:25:57 -0400 Received: from metis.ext.pengutronix.de ([85.220.165.71]:42637 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729594AbgC3IZ4 (ORCPT ); Mon, 30 Mar 2020 04:25:56 -0400 Received: from ptx.hi.pengutronix.de ([2001:67c:670:100:1d::c0]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jIpjy-00021V-UM; Mon, 30 Mar 2020 10:25:50 +0200 Received: from mgr by ptx.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1jIpjw-0002dB-LS; Mon, 30 Mar 2020 10:25:48 +0200 Date: Mon, 30 Mar 2020 10:25:48 +0200 From: Michael Grzeschik To: Felipe Balbi Cc: lars@metafoo.de, alexandru.Ardelean@analog.com, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, gregkh@linuxfoundation.org, bigeasy@linutronix.de, m.olbrich@pengutronix.de, kernel@pengutronix.de Subject: Re: [PATCH] usb: dwc3: gadget: don't dequeue requests on already disabled endpoints Message-ID: <20200330082548.GL27849@pengutronix.de> References: <20200327084302.606-1-m.grzeschik@pengutronix.de> <875zeokhoa.fsf@kernel.org> <20200329190244.GK27849@pengutronix.de> <87sghq2tum.fsf@kernel.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="wZdghQXYJzyo6AGC" Content-Disposition: inline In-Reply-To: <87sghq2tum.fsf@kernel.org> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 09:41:05 up 39 days, 15:11, 80 users, load average: 1.00, 0.56, 0.31 User-Agent: Mutt/1.10.1 (2018-07-13) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c0 X-SA-Exim-Mail-From: mgr@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --wZdghQXYJzyo6AGC Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Mar 30, 2020 at 10:18:57AM +0300, Felipe Balbi wrote: >=20 > Hi, >=20 > Michael Grzeschik writes: > >> > dwc3_gadget_ep_disable gets called before the last request gets > >> > dequeued. > >> > > >> > In __dwc3_gadget_ep_disable all started, pending and cancelled > >> > lists for this endpoint will call dwc3_gadget_giveback in > >> > dwc3_remove_requests. > >> > > >> > After that no list containing the afterwards dequed request, > >> > therefor it is not necessary to run the dequeue routine. > >> > > >> > Signed-off-by: Michael Grzeschik > >> > --- > >> > @Lars-Peter Clausen: > >> > > >> > This patch addresses the case that not queued requests get dequeued. > >> > The only case that this happens seems on disabling the gadget. > >> > > >> > drivers/usb/dwc3/gadget.c | 3 +++ > >> > 1 file changed, 3 insertions(+) > >> > > >> > diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c > >> > index 9a6f741d1db0dc..5d4fa8d6c93e49 100644 > >> > --- a/drivers/usb/dwc3/gadget.c > >> > +++ b/drivers/usb/dwc3/gadget.c > >> > @@ -1609,6 +1609,9 @@ static int dwc3_gadget_ep_dequeue(struct usb_e= p *ep, > >> > =20 > >> > trace_dwc3_ep_dequeue(req); > >> > =20 > >> > + if (!(dep->flags & DWC3_EP_ENABLED)) > >> > + return 0; > >>=20 > >> which driver is trying to call dequeue after the endpoint is disabled? > >> Got some tracepoints of the problem happening? > > > > I see the case when using uvc-gadget. > > > > Look into uvc_v4l2_release in uvc_v4l2.c: > > > > uvc_function_disconnect > > composite_disconnect > > reset_config > > uvc_function_disable->usb_ep_disable > > > > uvcg_video_enable > > usb_ep_dequeue > > dwc3_gadget_ep_dequeue >=20 > Oh, I see what you mean. We get a disconnect, which disables the > endpoints, which forces all requests to be dequeued. Now I remember why > this exists: we giveback the requests from disconnect because not all > gadget drivers will call usb_ep_dequeue() if simply told about the > disconnect. Then UDC drivers have to be a little more careful and make > sure that all requests are givenback. >=20 > In any case, why is it a problem to call usb_ep_dequeue()? Is it only > because of that dev_err()? We could just remove that message, > really. In my case, it is not a problem removing the dev_err. The ep_dequeue will only be called once for each request at the stream end. I don't know about the case Lars has mentioned. If we have to search all lists for the request every n times while in traffic, only to find out that it was not enqueued, I think it would be worth it to keep the dev_err and let these cases trigger so we have an option to find and avoid/fix these. > Eventually, I want to move more of this logic into UDC core so > udc drivers can be simplified. For that work, though, first we would > have to add a "generic" struct usb_ep_hw implementation and manage list > of requests as part of UDC core as well. I don't know about the cases you plan to abstract but it sounds like a good idea to get some gadget logic out of the drivers. Thanks, Michael --=20 Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | --wZdghQXYJzyo6AGC Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEElXvEUs6VPX6mDPT8C+njFXoeLGQFAl6BrQUACgkQC+njFXoe LGTnRQ/+MzuaYcXWW6Wcfj5AJjiqb9RuzdHPUCrc48bZJFhaDOoJwO/eJ9C9zZM0 /AAXJi9e/f89wRvMAQ1CyN6qT2SPqYxlZSKO4zuFyjyuslfujPCg4r372zisXFQJ mJpLileNOs8meBP4jfaD6ikGC5Vqb4J1YK7JX7dWAiqOKeJ1xFWTaU/QrQxwYVzU uL8PB/EZf/Y8EQrYIOaln0DvbJuVNllpK2uzwkjSnEe1lM9VCeiMcD+GJB+kkkNd dpATvxEqhVBWq9Xu0biwcWWrDfLtYBccxNd77Qy7IPIYWTiWHJaQFrkijsj5TevY oGWIZ/UvzUrSssu6VUgLXhoi1xaizjnGprL9WY2vx6E5nOiuUpWqQ8A/ahukuG58 S01liCaic7NjcNyPtAO+zLaZt+oR06WO/t2B7GArhnTY7o4l69zGIIkRvUhYc94z o42iUvghfbCXHmQaqK9ar3cT0brFmYDTm7vEJxpAPJbKKkgkmqPCqSqQOKp3iYF7 dgrVLdC1tvtoCiA51OPitqVttoyJZsLmRTGQbvExI54sqgh4ynJh7031SbPEd59Z T8oCl/fAoTZG4xWthYZUFP+uXAF/ALzMIyi3ggwJA4dJKc1q8GZ7aCOV52na8Lpl sqoEAw20vuLEXDfuwKT5FkyCWIQ6szWYn+U5wExMzV7zdvjZxg8= =ON5s -----END PGP SIGNATURE----- --wZdghQXYJzyo6AGC--