From patchwork Mon Feb 8 15:00:52 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 379247 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=-19.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT 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 8DB3FC43381 for ; Mon, 8 Feb 2021 15:10:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 565A664EFD for ; Mon, 8 Feb 2021 15:10:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232787AbhBHPJ6 (ORCPT ); Mon, 8 Feb 2021 10:09:58 -0500 Received: from mail.kernel.org ([198.145.29.99]:52656 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231723AbhBHPHD (ORCPT ); Mon, 8 Feb 2021 10:07:03 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 4851864EBD; Mon, 8 Feb 2021 15:05:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1612796734; bh=uNdtUiPu/JXuxmabfk74niAlwlkvOOeoAi5s2CdvdPk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=J6HDwnXba5lTeJEH2aNzHJkyRkmJ5lJ0GrIX+6xIk0WwfGFtJWAyayV0CSOL4uXQb Dc8G0frhMuROYGPUXo8ukUsn5w94HvBFEp+Evsb02egNH3NFpuWpVqCdHrj9B8M0Wn 2rbhUPdx3z284mWVCXuXPmukcRu4KHe4kDn/C04k= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Pete Zaitcev , Jeremy Figgins Subject: [PATCH 4.9 26/43] USB: usblp: dont call usb_set_interface if theres a single alt Date: Mon, 8 Feb 2021 16:00:52 +0100 Message-Id: <20210208145807.382485465@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210208145806.281758651@linuxfoundation.org> References: <20210208145806.281758651@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jeremy Figgins commit d8c6edfa3f4ee0d45d7ce5ef18d1245b78774b9d upstream. Some devices, such as the Winbond Electronics Corp. Virtual Com Port (Vendor=0416, ProdId=5011), lockup when usb_set_interface() or usb_clear_halt() are called. This device has only a single altsetting, so it should not be necessary to call usb_set_interface(). Acked-by: Pete Zaitcev Signed-off-by: Jeremy Figgins Link: https://lore.kernel.org/r/YAy9kJhM/rG8EQXC@watson Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/usb/class/usblp.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) --- a/drivers/usb/class/usblp.c +++ b/drivers/usb/class/usblp.c @@ -1349,14 +1349,17 @@ static int usblp_set_protocol(struct usb if (protocol < USBLP_FIRST_PROTOCOL || protocol > USBLP_LAST_PROTOCOL) return -EINVAL; - alts = usblp->protocol[protocol].alt_setting; - if (alts < 0) - return -EINVAL; - r = usb_set_interface(usblp->dev, usblp->ifnum, alts); - if (r < 0) { - printk(KERN_ERR "usblp: can't set desired altsetting %d on interface %d\n", - alts, usblp->ifnum); - return r; + /* Don't unnecessarily set the interface if there's a single alt. */ + if (usblp->intf->num_altsetting > 1) { + alts = usblp->protocol[protocol].alt_setting; + if (alts < 0) + return -EINVAL; + r = usb_set_interface(usblp->dev, usblp->ifnum, alts); + if (r < 0) { + printk(KERN_ERR "usblp: can't set desired altsetting %d on interface %d\n", + alts, usblp->ifnum); + return r; + } } usblp->bidir = (usblp->protocol[protocol].epread != NULL);