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=-17.6 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_IN_DEF_DKIM_WL 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 BD6B9C433E0 for ; Tue, 11 Aug 2020 23:22:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8705F20774 for ; Tue, 11 Aug 2020 23:22:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="NwTyzfGG" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726179AbgHKXWg (ORCPT ); Tue, 11 Aug 2020 19:22:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48424 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726115AbgHKXWe (ORCPT ); Tue, 11 Aug 2020 19:22:34 -0400 Received: from mail-vs1-xe41.google.com (mail-vs1-xe41.google.com [IPv6:2607:f8b0:4864:20::e41]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4EA7CC06174A for ; Tue, 11 Aug 2020 16:22:34 -0700 (PDT) Received: by mail-vs1-xe41.google.com with SMTP id p8so160177vsm.12 for ; Tue, 11 Aug 2020 16:22:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=M8tHIq10qcvL+DPe0+2tp6gdA5jLeIeYfiy2N8zjReI=; b=NwTyzfGGVaq1LMhjX+eMHHZ4teSqnqq4A4a9m4XDH7d0CRzMwopcWJusMPKXZwRZoe 0oPhsf+zgJzXzg1ZTNeE5O08jEmpGcGHBeRHodrkm+1GXjgt0MA47Clg5JRYQlFOlWsz P9f50Nvb1Q7cn1fPFnDZ/U8msiM9fzXsga7iJ/VNNKWYw6WOHVICVcq9sx06Oo8rup9K 3I3PpKiqkVstOGdeYtvsOKlrJyF7NL123816TG9FeZ7SBdvXHl4RqWviKXFK3IQHPJZR eXMxnd1/7UYVvFM71w3wjB9NeojTnWaJtwBc/QpS9aEcZfbiuEpS4j5z2NZBHEiYjUpr HpkQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=M8tHIq10qcvL+DPe0+2tp6gdA5jLeIeYfiy2N8zjReI=; b=nR3fd1KhdkHQ+clJf+1wc4fnkfbGMvsK2l55F5L9JNIVQ0P1wMAN+OJrHL1y32Nv3p dJ06hpb2g1TNJoz/vQV3vU+soSPX5BDGko13oOZAjdp+sWurQKJI9L8cNxO8mmPxJxdn 1ZSxIApD8xDNJCzIIXxE4IYD7nJfn1FC9Mw0KNFseRDssTGE7RFmftBMGejhbPOpsdgw J8bYBcI/yYY96pJ2ISXjlUBFgb5yk3VldYwFWLvmp3niHy2/3jNpJMXsGiiWoTFvyy+/ KZvWj6r+bH+cpTxisj4BgEFhnKH+5uq1l83MGdlRMtnDH72ccol02vT9EMfWoPAg0ln+ NJqw== X-Gm-Message-State: AOAM5338v6ombbCF6Qvsy24d8WSXZx/8m3xZD5Z9I4cvjyuBnPLjEXFn avw4q2OVGjtfXaim7w23dDQiD/1Ld5ttn1iQdaU+eQ== X-Google-Smtp-Source: ABdhPJwekl2Qum8Yq7I+RnVMOd6HHvCiYCBoHr0z+I6Yw/vHPbdxyOfAeQO0cvHyPJsgkDK44muhBYtZoZ3wbYxw4V4= X-Received: by 2002:a67:ec13:: with SMTP id d19mr23820388vso.28.1597188153223; Tue, 11 Aug 2020 16:22:33 -0700 (PDT) MIME-Version: 1.0 References: <20200811011126.130297-1-badhri@google.com> <20200811184507.GB86545@roeck-us.net> <8a2e77f4-1470-ebf0-402c-df90ab6332bb@roeck-us.net> In-Reply-To: <8a2e77f4-1470-ebf0-402c-df90ab6332bb@roeck-us.net> From: Badhri Jagan Sridharan Date: Tue, 11 Aug 2020 16:21:57 -0700 Message-ID: Subject: Re: [PATCH v1] usb: typec: tcpm: Fix TDA 2.2.1.1 and TDA 2.2.1.2 failures To: Guenter Roeck Cc: Heikki Krogerus , Greg Kroah-Hartman , USB , LKML Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Thanks Guenter ! However I don't see a reviewed-by tag :) On Tue, Aug 11, 2020 at 1:18 PM Guenter Roeck wrote: > > On 8/11/20 12:39 PM, Badhri Jagan Sridharan wrote: > > On Tue, Aug 11, 2020 at 11:45 AM Guenter Roeck wrote: > >> > >> On Tue, Aug 11, 2020 at 11:24:07AM -0700, Badhri Jagan Sridharan wrote: > >>> On Mon, Aug 10, 2020 at 6:51 PM Guenter Roeck wrote: > >>>> > >>>> On 8/10/20 6:11 PM, Badhri Jagan Sridharan wrote: > >>>>> >From the spec: > >>>>> "7.1.5 Response to Hard Resets > >>>>> Hard Reset Signaling indicates a communication failure has occurred and > >>>>> the Source Shall stop driving VCONN, Shall remove Rp from the VCONN pin > >>>>> and Shall drive VBUS to vSafe0V as shown in Figure 7-9. The USB connection > >>>>> May reset during a Hard Reset since the VBUS voltage will be less than > >>>>> vSafe5V for an extended period of time. After establishing the vSafe0V > >>>>> voltage condition on VBUS, the Source Shall wait tSrcRecover before > >>>>> re-applying VCONN and restoring VBUS to vSafe5V. A Source Shall conform > >>>>> to the VCONN timing as specified in [USB Type-C 1.3]." > >>>>> > >>>>> Signed-off-by: Badhri Jagan Sridharan > >>>>> --- > >>>>> drivers/usb/typec/tcpm/tcpm.c | 16 +++++++++++++--- > >>>>> 1 file changed, 13 insertions(+), 3 deletions(-) > >>>>> > >>>>> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c > >>>>> index 3ef37202ee37..e41c4e5d3c71 100644 > >>>>> --- a/drivers/usb/typec/tcpm/tcpm.c > >>>>> +++ b/drivers/usb/typec/tcpm/tcpm.c > >>>>> @@ -3372,13 +3372,19 @@ static void run_state_machine(struct tcpm_port *port) > >>>>> tcpm_set_state(port, SNK_HARD_RESET_SINK_OFF, 0); > >>>>> break; > >>>>> case SRC_HARD_RESET_VBUS_OFF: > >>>>> - tcpm_set_vconn(port, true); > >>>>> + /* > >>>>> + * 7.1.5 Response to Hard Resets > >>>>> + * Hard Reset Signaling indicates a communication failure has occurred and the > >>>>> + * Source Shall stop driving VCONN, Shall remove Rp from the VCONN pin and Shall > >>>>> + * drive VBUS to vSafe0V as shown in Figure 7-9. > >>>>> + */ > >>>>> + tcpm_set_vconn(port, false); > >>>>> tcpm_set_vbus(port, false); > >>>>> tcpm_set_roles(port, port->self_powered, TYPEC_SOURCE, > >>>>> tcpm_data_role_for_source(port)); > >>>>> - tcpm_set_state(port, SRC_HARD_RESET_VBUS_ON, PD_T_SRC_RECOVER); > >>>> > >>>> I am a bit concerned about this. If I understand correctly, it means that > >>>> we won't turn VBUS back on unless a SRC_HARD_RESET_VBUS_OFF PD event is received. > >>>> Is that correct ? What happens if that event is never received ? > >>>> > >>>> Thanks, > >>>> Guenter > >>> > >>> The term PD event is a little ambiguous to me. Trying to summarize the workflow. > >>> Lower level tcpc driver would have to call tcpm_vbus_change which > >>> would in-turn trigger TCPM_VBUS_EVENT > >>> and queries port->tcpc->get_vbus to get the vbus status. It is not > >>> really a PD protocol driven event hence the > >>> confusion. > >>> > >>> "What happens if that event is never received ?" > >>> Yeah TCPM would be in SRC_HARD_RESET_VBUS_OFF till the tcpc calls the > >>> tcpm_vbus_change. > >>> Do you suspect that existing tcpc would not have the capability to > >>> monitor vbus status while sourcing and call tcpm_vbus_change? > >>> > >> That, or the driver might be buggy, or the hardware does't signal a status > >> update, or the update gets lost. I think we should have some backup, > >> to trigger if the event is not received in a reasonable amout of time. > >> I don't know if the specification has some kind of maximum limit. If > >> not, we should still have something > >> > >> Thanks, > >> Guenter > > > > Got it ! The specification actually has a bound for vbus off. > > tSafe0V - Time to reach vSafe0V max - 650ms. (PD_T_SAFE_0V). > > So I will bound it to that. > > > > Excellent. Thanks a lot for looking into this! > > Guenter > > >>From Table 7-12 Sequence Description for a Source Initiated Hard Reset: > > 4.Policy Engine waits tPSHardReset after sending Hard Reset Signaling > > and then tells the Device Policy Manager to instruct the power supply > > to perform a Hard Reset. The transition to vSafe0V Shall occur within > > tSafe0V (t2). > > 5 After tSrcRecover the Source applies power to VBUS in an attempt to > > re-establish communication with the Sink and resume USB Default > > Operation. The transition to vSafe5V Shall occur within tSrcTurnOn > > (t4). > > > > Thanks, > > Badhri > > > >> > >>> Thanks, > >>> Badhri > >>> > >>> > >>>>> break; > >>>>> case SRC_HARD_RESET_VBUS_ON: > >>>>> + tcpm_set_vconn(port, true); > >>>>> tcpm_set_vbus(port, true); > >>>>> port->tcpc->set_pd_rx(port->tcpc, true); > >>>>> tcpm_set_attached_state(port, true); > >>>>> @@ -3944,7 +3950,11 @@ static void _tcpm_pd_vbus_off(struct tcpm_port *port) > >>>>> tcpm_set_state(port, SNK_HARD_RESET_WAIT_VBUS, 0); > >>>>> break; > >>>>> case SRC_HARD_RESET_VBUS_OFF: > >>>>> - tcpm_set_state(port, SRC_HARD_RESET_VBUS_ON, 0); > >>>>> + /* > >>>>> + * After establishing the vSafe0V voltage condition on VBUS, the Source Shall wait > >>>>> + * tSrcRecover before re-applying VCONN and restoring VBUS to vSafe5V. > >>>>> + */ > >>>>> + tcpm_set_state(port, SRC_HARD_RESET_VBUS_ON, PD_T_SRC_RECOVER); > >>>>> break; > >>>>> case HARD_RESET_SEND: > >>>>> break; > >>>>> > >>>> >