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=-5.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham 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 0D255C43387 for ; Mon, 14 Jan 2019 05:11:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CABF420659 for ; Mon, 14 Jan 2019 05:11:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="u9Dz3Tie" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726522AbfANFLX (ORCPT ); Mon, 14 Jan 2019 00:11:23 -0500 Received: from perceval.ideasonboard.com ([213.167.242.64]:35994 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725910AbfANFLX (ORCPT ); Mon, 14 Jan 2019 00:11:23 -0500 Received: from localhost.localdomain (unknown [96.44.9.117]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 74FA7505; Mon, 14 Jan 2019 06:11:19 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1547442680; bh=esYPm4b0uDdBX5f/Z8E07u3/w+FPQbC3SDb9m+cNhaw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=u9Dz3TieCLdVPwgi1YF+nMtdIJB/H+aPWNsxMgeRi4bBGMUGPvtWSd8odlNSBhwyh bVUg/3KH9sEyaUXFgH96bF1y9EXHJ3DAiIEhW1CGG8xqD5xHLpYi4hut6aVzTE+5SD obuB35ZGRPK5XnNRNp6gRRr0vMg+NN0vM2aif+9A= Date: Mon, 14 Jan 2019 00:11:13 -0500 From: Paul Elder To: Alan Stern Cc: laurent.pinchart@ideasonboard.com, kieran.bingham@ideasonboard.com, b-liu@ti.com, rogerq@ti.com, balbi@kernel.org, gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 4/6] usb: gadget: add mechanism to specify an explicit status stage Message-ID: <20190114051113.GD32268@localhost.localdomain> References: <20190111082340.GB32268@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 11, 2019 at 10:50:11AM -0500, Alan Stern wrote: > On Fri, 11 Jan 2019, Paul Elder wrote: > > > On Wed, Jan 09, 2019 at 02:06:31PM -0500, Alan Stern wrote: > > > On Wed, 9 Jan 2019, Paul Elder wrote: > > > > > > > A usb gadget function driver may or may not want to delay the status > > > > stage of a control OUT request. An instance where it might want to is to > > > > asynchronously validate the data of a class-specific request. > > > > > > > > A function driver that wants an explicit status stage should set the > > > > newly added explicit_status flag of the usb_request corresponding to the > > > > data stage. Later on, the function driver can explicitly complete the > > > > status stage by enqueueing a usb_request for ACK, or calling > > > > usb_ep_set_halt() for STALL. > > > > > > > > To support both explicit and implicit status stages, a UDC driver must > > > > call the newly added usb_gadget_control_complete function right before > > > > calling usb_gadget_giveback_request. To support the explicit status > > > > stage, it might then check what stage the usb_request was queued in, and > > > > for control IN ACK the host's zero-length data packet, or for control > > > > OUT send a zero-length DATA1 ACK packet. > > > > > > > > Signed-off-by: Paul Elder > > > > v4 Acked-by: Alan Stern > > > > v1 Reviewed-by: Laurent Pinchart > > > > > > This looks good and has passed my tests so far. > > > > Good! Thank you :) > > > > > Can you check your uvc > > > changes using dummy_hcd with the patch below? > > > > I'm not sure what to make of the test results. I get the same results > > with or without the patch. Which I guess makes sense... in dummy_queue, > > this is getting hit when the uvc function driver tries to complete the > > delayed status: > > > > req = usb_request_to_dummy_request(_req); > > if (!_req || !list_empty(&req->queue) || !_req->complete) > > return -EINVAL; > > > > So the delayed/explicit status stage is never completed, afaict. > > I presume you are hitting the !list_empty(&req->queue) test, yes? The > other two tests are trivial. Yes, that is what's happening. > Triggering the !list_empty() test means the request has already been > submitted and not yet completed. This probably indicates there is a > bug in the uvc function driver code. The uvc function driver works with musb, though :/ I compared the sequence of calls to the uvc setup, completion handler, and status stage sending, and for some reason dummy_hcd, after an OUT setup-completion-status sequence, calls a completion-status-completion sequence, and then goes on the the next request. musb simply goes on to the next request after the setup-completion-status sequence. I commented out the paranoia block in dummy_timer, and dummy_hcd still does the extra completion, but it doesn't error out anymore. I doubt that's the/a solution though, especially since I get: [ 22.616577] uvcvideo: Failed to query (129) UVC probe control : -75 (exp. 26). [ 22.624481] uvcvideo: Failed to initialize the device (-5). Not sure if that's a result of dummy_hcd not supporting isochronous transfers or not. I'm not sure where to continue investigating :/ Thanks, Paul