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=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 310A1C2D0CE for ; Mon, 30 Dec 2019 16:07:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0924A2071E for ; Mon, 30 Dec 2019 16:07:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="NIqxuaZL" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727501AbfL3QHb (ORCPT ); Mon, 30 Dec 2019 11:07:31 -0500 Received: from mail-pg1-f194.google.com ([209.85.215.194]:42836 "EHLO mail-pg1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727471AbfL3QHb (ORCPT ); Mon, 30 Dec 2019 11:07:31 -0500 Received: by mail-pg1-f194.google.com with SMTP id s64so18198829pgb.9; Mon, 30 Dec 2019 08:07:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=QQifhEvd0qlOro5mq55/v6MzZxcRB/EQ8GzsSLDvKvQ=; b=NIqxuaZLjE0bnw2trLuyaKCZlOURs2/yVNquCgje//3TbuWs8CCcqgzfTuEQMYq5Gu IdC2MuXxAmVo7Ke2A8LTaJXUKNePtWGOW09awQrpPWIpUBYPlbd9OnRk4BPT8Hdd3vAc KrGMRAF+11XvtTWVQl1VOODUZuEv/qO/0lndaOrPSAaSuZF4DQ75WVukArcZmv2qaMXx SiRVh4bi0dIO96A2XKy1qYT4k8ODlb/W/zB+wBruI55Kdqz+/NHk9yb517H6OAKavRGp ww2lKDNMuyQwY1savCtFsgg1MlFNmm2FehvzRQvRXSn+vTBLRiGLxiNCFtNe9KV+5/CX sM8A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=QQifhEvd0qlOro5mq55/v6MzZxcRB/EQ8GzsSLDvKvQ=; b=Wx9V8BfWuedfE2xTbAS/bFm/fjJq/5RKEeOUMxXd+EMGvRPEQ4rKvGKi3+PDsOzvSv UcwbBBmNGEUFuQKdYoP+uNNVFsgA8GAEbRXZRXx6jv5dmdQZjVJsfShMRC4TPxCJdH8z TgAhiOiI6f6Kgr3asCuoJsU39JlyTgxuCoY5WK4Z9Y1q2izVkdPtEKhTT6TFxZuDtUj2 AiG+sZV2oOz6OpZiu461WOdJQ9VNtBYVx9C0MuTkfaR4bsaJOjh0cMu5mi/JXms5A1bd xffqlRiPq0kNvWPK4s+HBMiNyB5RvMZvNXzzsigBpDSNaXljlmP0V2Sl98RukZMeqUEd R1Pg== X-Gm-Message-State: APjAAAVr2FJCjYRUdGaqVlq/SkNEjfkmx+UDfqZ208lAQDBUxOiPfYSV 2uTcTJ+twExcvBns9/IcmqCX+msW X-Google-Smtp-Source: APXvYqw5acYxqgdINUs+FyQDAeNUkty8IHAD+FtPNa+5uPBm42ipxImSwOPnn/wLQLHeIRF091ukpw== X-Received: by 2002:a63:6fca:: with SMTP id k193mr75185418pgc.416.1577722050295; Mon, 30 Dec 2019 08:07:30 -0800 (PST) Received: from localhost ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id t63sm52734279pfb.70.2019.12.30.08.07.28 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 30 Dec 2019 08:07:29 -0800 (PST) Date: Mon, 30 Dec 2019 08:07:27 -0800 From: Guenter Roeck To: Douglas Gilbert Cc: linux-usb@vger.kernel.org, stable@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] USB-PD tcpm: bad warning+size, PPS adapters Message-ID: <20191230160727.GA12958@roeck-us.net> References: <20191230033544.1809-1-dgilbert@interlog.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191230033544.1809-1-dgilbert@interlog.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Sun, Dec 29, 2019 at 10:35:44PM -0500, Douglas Gilbert wrote: > Augmented Power Delivery Objects (A)PDO_s are used by USB-C > PD power adapters to advertize the voltages and currents > they support. There can be up to 7 PDO_s but before PPS > (programmable power supply) there were seldom more than 4 > or 5. Recently Samsung released an optional PPS 45 Watt power > adapter (EP-TA485) that has 7 PDO_s. It is for the Galaxy 10+ > tablet and charges it quicker than the adapter supplied at > purchase. The EP-TA485 causes an overzealous WARN_ON to soil > the log plus it miscalculates the number of bytes to read. > > So this bug has been there for some time but goes > undetected for the majority of USB-C PD power adapters on > the market today that have 6 or less PDO_s. That may soon > change as more USB-C PD adapters with PPS come to market. > > Tested on a EP-TA485 and an older Lenovo PN: SA10M13950 > USB-C 65 Watt adapter (without PPS and has 4 PDO_s) plus > several other PD power adapters. > > Signed-off-by: Douglas Gilbert Reviewed-by: Guenter Roeck > --- > drivers/usb/typec/tcpm/tcpci.c | 20 +++++++++++++++----- > 1 file changed, 15 insertions(+), 5 deletions(-) > > diff --git a/drivers/usb/typec/tcpm/tcpci.c b/drivers/usb/typec/tcpm/tcpci.c > index c1f7073a56de..8b4ff9fff340 100644 > --- a/drivers/usb/typec/tcpm/tcpci.c > +++ b/drivers/usb/typec/tcpm/tcpci.c > @@ -432,20 +432,30 @@ irqreturn_t tcpci_irq(struct tcpci *tcpci) > > if (status & TCPC_ALERT_RX_STATUS) { > struct pd_message msg; > - unsigned int cnt; > + unsigned int cnt, payload_cnt; > u16 header; > > regmap_read(tcpci->regmap, TCPC_RX_BYTE_CNT, &cnt); > + /* > + * 'cnt' corresponds to READABLE_BYTE_COUNT in section 4.4.14 > + * of the TCPCI spec [Rev 2.0 Ver 1.0 October 2017] and is > + * defined in table 4-36 as one greater than the number of > + * bytes received. And that number includes the header. So: > + */ > + if (cnt > 3) > + payload_cnt = cnt - (1 + sizeof(msg.header)); > + else > + payload_cnt = 0; > > tcpci_read16(tcpci, TCPC_RX_HDR, &header); > msg.header = cpu_to_le16(header); > > - if (WARN_ON(cnt > sizeof(msg.payload))) > - cnt = sizeof(msg.payload); > + if (WARN_ON(payload_cnt > sizeof(msg.payload))) > + payload_cnt = sizeof(msg.payload); > > - if (cnt > 0) > + if (payload_cnt > 0) > regmap_raw_read(tcpci->regmap, TCPC_RX_DATA, > - &msg.payload, cnt); > + &msg.payload, payload_cnt); > > /* Read complete, clear RX status alert bit */ > tcpci_write16(tcpci, TCPC_ALERT, TCPC_ALERT_RX_STATUS); > -- > 2.24.1 >