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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 6570BC33CB1 for ; Tue, 14 Jan 2020 10:14:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2F12D20678 for ; Tue, 14 Jan 2020 10:14:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578996890; bh=jMxOhpWReMdooUfFA0VgQedI3t3wXCKo7DdVSS9QIQU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=kLNMOykTLN3FvZf+qU2g7LUeTMtorxhzXhHOpGmvtipmc+/Ds2jKe4+bLXsD4lxRc mo3ToL8OuatVYN9ZeNVBB6VAsGl9RSQP7pkGUy8Rz3OTUqiG/zVj3PMQF1bLvbXKpD STYz7sP7MOJ5biJnDE37XJNRDdA93X3Ys+fvsNwA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730937AbgANKLx (ORCPT ); Tue, 14 Jan 2020 05:11:53 -0500 Received: from mail.kernel.org ([198.145.29.99]:47606 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731893AbgANKLx (ORCPT ); Tue, 14 Jan 2020 05:11:53 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0DA9A24679; Tue, 14 Jan 2020 10:11:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578996712; bh=jMxOhpWReMdooUfFA0VgQedI3t3wXCKo7DdVSS9QIQU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Veu0RE5KYNtCDrfNUC33Hbt+rNTE8AIAeee0LSerRyDBD5gS4UphsBXEQdN1FXoRk 0XwpT5KkIBN3uHi5wSkvXRQXbD3a2VPqQ1S94KSVYTtB17MOcZ65S6wK4SxIaWNm9E KSAqsz/VSeO6bd44PQDB+jupn/9vjn2jzbHtHs38= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alan Stern , Laurent Pinchart , Roger Whittaker Subject: [PATCH 4.9 29/31] USB: Fix: Dont skip endpoint descriptors with maxpacket=0 Date: Tue, 14 Jan 2020 11:02:21 +0100 Message-Id: <20200114094345.439636433@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200114094334.725604663@linuxfoundation.org> References: <20200114094334.725604663@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Alan Stern commit 2548288b4fb059b2da9ceada172ef763077e8a59 upstream. It turns out that even though endpoints with a maxpacket length of 0 aren't useful for data transfer, the descriptors do serve other purposes. In particular, skipping them will also skip over other class-specific descriptors for classes such as UVC. This unexpected side effect has caused some UVC cameras to stop working. In addition, the USB spec requires that when isochronous endpoint descriptors are present in an interface's altsetting 0 (which is true on some devices), the maxpacket size _must_ be set to 0. Warning about such things seems like a bad idea. This patch updates an earlier commit which would log a warning and skip these endpoint descriptors. Now we only log a warning, and we don't even do that for isochronous endpoints in altsetting 0. We don't need to worry about preventing endpoints with maxpacket = 0 from ever being used for data transfers; usb_submit_urb() already checks for this. Reported-and-tested-by: Roger Whittaker Fixes: d482c7bb0541 ("USB: Skip endpoints with 0 maxpacket length") Signed-off-by: Alan Stern CC: Laurent Pinchart Link: https://marc.info/?l=linux-usb&m=157790377329882&w=2 Link: https://lore.kernel.org/r/Pine.LNX.4.44L0.2001061040270.1514-100000@iolanthe.rowland.org Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/config.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) --- a/drivers/usb/core/config.c +++ b/drivers/usb/core/config.c @@ -387,12 +387,16 @@ static int usb_parse_endpoint(struct dev endpoint->desc.wMaxPacketSize = cpu_to_le16(8); } - /* Validate the wMaxPacketSize field */ + /* + * Validate the wMaxPacketSize field. + * Some devices have isochronous endpoints in altsetting 0; + * the USB-2 spec requires such endpoints to have wMaxPacketSize = 0 + * (see the end of section 5.6.3), so don't warn about them. + */ maxp = usb_endpoint_maxp(&endpoint->desc); - if (maxp == 0) { - dev_warn(ddev, "config %d interface %d altsetting %d endpoint 0x%X has wMaxPacketSize 0, skipping\n", + if (maxp == 0 && !(usb_endpoint_xfer_isoc(d) && asnum == 0)) { + dev_warn(ddev, "config %d interface %d altsetting %d endpoint 0x%X has invalid wMaxPacketSize 0\n", cfgno, inum, asnum, d->bEndpointAddress); - goto skip_to_next_endpoint_or_interface_descriptor; } /* Find the highest legal maxpacket size for this endpoint */