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=-23.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 4529CC433ED for ; Wed, 14 Apr 2021 00:59:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 21F1161166 for ; Wed, 14 Apr 2021 00:59:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348910AbhDNA7w (ORCPT ); Tue, 13 Apr 2021 20:59:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54984 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348901AbhDNA7v (ORCPT ); Tue, 13 Apr 2021 20:59:51 -0400 Received: from mail-vs1-xe36.google.com (mail-vs1-xe36.google.com [IPv6:2607:f8b0:4864:20::e36]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C53F1C061756 for ; Tue, 13 Apr 2021 17:59:30 -0700 (PDT) Received: by mail-vs1-xe36.google.com with SMTP id r18so3598839vso.12 for ; Tue, 13 Apr 2021 17:59:30 -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=y/54ILv5Q72An34zKDPTFESYNXFuudb6GNqLTSzT03Y=; b=CD8jNA/CwaQxyYuthSMMfMZpaVUZR2GZiWtJsXZ52SSSLXN/jzrZplLASx/kNE/EBM Aamv9Y3Sv7LmmjmZ4BSjuqthpjBvgo5eRI0JMRZ+KxbA87zHj1bRYv02e4dO8LHhEeTl TMtOpsFlBPmCY7V4UVWS2CMjIDLlzC1MdyqoGTeucbjYZt/q7OFg4+XCl4NJfeeYvMHb 6yjj7fUpf4vfbSRPpsT81KWrZgXALIw10zseLHdDqAPIhhGOkvBpS5bLv402rzipm85r kcCKjrh5NYQSSUCQIaLCIyFjkwNsgwXZGfX0tdUPqe50miff3mdU3UZO8fvAeaUy5WDn V/fg== 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=y/54ILv5Q72An34zKDPTFESYNXFuudb6GNqLTSzT03Y=; b=Zu/cSXvdjkzC+ovrgQk4V9TodawNFTbTnDZouQBVpefuK3LsFu/INhlWBePQaMnOxX gWNCrvZwr5kU0I9nlSd1PbFtLa/X4frHo8JhURRdUkjRBdDYgbKAtIc1EQbLj6SAYpaa iq3y87Px8nRuAR3tKHnRCgmZ8fnGTG+fkYTohmmULFP8yi8K35M183t7aE1+gPszi+aw UxRUTcVqpFC/mO8GnU5YYg9EWycC6WCkVFnVE0ZBwqvJ8/tIj0/VEuQzSTpOuCHuxsSZ yCP+pAyAvAifSS5MnRqRz6ibUPFjTQjRZYGx/Hmba+iTwE67fCa0yR8i2SKUJAuch1T/ tWIg== X-Gm-Message-State: AOAM530wgSrrDN2GtIPVXBM5uEJjtEwWPtrKltJcM5FJVt72jv+0Cbyf 2XMtWoOoxbCkKkpOWhgtExUj1bnYag1dzjEjqHQBqI2LyHBvSw== X-Google-Smtp-Source: ABdhPJzoRlLgGDRdvSA7gaqK4TOeAzpTt3J3nsLaQ3IVJCjYTp9P41srxdWa1+FAp4wB+e1i5FracvZv0O6XVGDg48U= X-Received: by 2002:a67:ee08:: with SMTP id f8mr18327069vsp.58.1618361969412; Tue, 13 Apr 2021 17:59:29 -0700 (PDT) MIME-Version: 1.0 References: <20210407200723.1914388-1-badhri@google.com> <20210407200723.1914388-4-badhri@google.com> In-Reply-To: From: Badhri Jagan Sridharan Date: Tue, 13 Apr 2021 17:58:54 -0700 Message-ID: Subject: Re: [PATCH v2 4/6] usb: typec: tcpm: Honour pSnkStdby requirement during negotiation To: Heikki Krogerus Cc: Guenter Roeck , Greg Kroah-Hartman , Rob Herring , Adam Thomson , USB , LKML , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , Kyle Tso Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Thu, Apr 8, 2021 at 12:48 AM Heikki Krogerus wrote: > > On Wed, Apr 07, 2021 at 01:07:21PM -0700, Badhri Jagan Sridharan wrote: > > >From PD Spec: > > The Sink Shall transition to Sink Standby before a positive or > > negative voltage transition of VBUS. During Sink Standby > > the Sink Shall reduce its power draw to pSnkStdby. This allows > > the Source to manage the voltage transition as well as > > supply sufficient operating current to the Sink to maintain PD > > operation during the transition. The Sink Shall > > complete this transition to Sink Standby within tSnkStdby > > after evaluating the Accept Message from the Source. The > > transition when returning to Sink operation from Sink Standby > > Shall be completed within tSnkNewPower. The > > pSnkStdby requirement Shall only apply if the Sink power draw > > is higher than this level. > > > > The above requirement needs to be met to prevent hard resets > > from port partner. > > > > Without the patch: (5V/3A during SNK_DISCOVERY all the way through > > explicit contract) > > [ 95.711984] CC1: 0 -> 0, CC2: 0 -> 5 [state TOGGLING, polarity 0, connected] > > [ 95.712007] state change TOGGLING -> SNK_ATTACH_WAIT [rev3 NONE_AMS] > > [ 95.712017] pending state change SNK_ATTACH_WAIT -> SNK_DEBOUNCED @ 170 ms [rev3 NONE_AMS] > > [ 95.837190] VBUS on > > [ 95.882075] state change SNK_ATTACH_WAIT -> SNK_DEBOUNCED [delayed 170 ms] > > [ 95.882082] state change SNK_DEBOUNCED -> SNK_ATTACHED [rev3 NONE_AMS] > > [ 95.882086] polarity 1 > > [ 95.883151] set_auto_vbus_discharge_threshold mode:0 pps_active:n vbus:5000 ret:0 > > [ 95.883441] enable vbus discharge ret:0 > > [ 95.883445] Requesting mux state 1, usb-role 2, orientation 2 > > [ 95.883776] state change SNK_ATTACHED -> SNK_STARTUP [rev3 NONE_AMS] > > [ 95.883879] pending state change SNK_STARTUP -> SNK_DISCOVERY @ 500 ms [rev3 NONE_AMS] > > [ 96.038960] VBUS on > > [ 96.383939] state change SNK_STARTUP -> SNK_DISCOVERY [delayed 500 ms] > > [ 96.383946] Setting voltage/current limit 5000 mV 3000 mA > > [ 96.383961] vbus=0 charge:=1 > > [ 96.386044] state change SNK_DISCOVERY -> SNK_WAIT_CAPABILITIES [rev3 NONE_AMS] > > [ 96.386309] pending state change SNK_WAIT_CAPABILITIES -> HARD_RESET_SEND @ 450 ms [rev3 NONE_AMS] > > [ 96.394404] PD RX, header: 0x2161 [1] > > [ 96.394408] PDO 0: type 0, 5000 mV, 3000 mA [E] > > [ 96.394410] PDO 1: type 0, 9000 mV, 2000 mA [] > > [ 96.394412] state change SNK_WAIT_CAPABILITIES -> SNK_NEGOTIATE_CAPABILITIES [rev2 POWER_NEGOTIATION] > > [ 96.394416] Setting usb_comm capable false > > [ 96.395083] cc=0 cc1=0 cc2=5 vbus=0 vconn=sink polarity=1 > > [ 96.395089] Requesting PDO 1: 9000 mV, 2000 mA > > [ 96.395093] PD TX, header: 0x1042 > > [ 96.397404] PD TX complete, status: 0 > > [ 96.397424] pending state change SNK_NEGOTIATE_CAPABILITIES -> HARD_RESET_SEND @ 60 ms [rev2 POWER_NEGOTIATION] > > [ 96.400826] PD RX, header: 0x363 [1] > > [ 96.400829] state change SNK_NEGOTIATE_CAPABILITIES -> SNK_TRANSITION_SINK [rev2 POWER_NEGOTIATION] > > [ 96.400832] pending state change SNK_TRANSITION_SINK -> HARD_RESET_SEND @ 500 ms [rev2 POWER_NEGOTIATION] > > [ 96.577315] PD RX, header: 0x566 [1] > > [ 96.577321] Setting voltage/current limit 9000 mV 2000 mA > > [ 96.578363] set_auto_vbus_discharge_threshold mode:3 pps_active:n vbus:9000 ret:0 > > [ 96.578370] state change SNK_TRANSITION_SINK -> SNK_READY [rev2 POWER_NEGOTIATION] > > > > With the patch: > > [ 168.398573] CC1: 0 -> 0, CC2: 0 -> 5 [state TOGGLING, polarity 0, connected] > > [ 168.398605] state change TOGGLING -> SNK_ATTACH_WAIT [rev3 NONE_AMS] > > [ 168.398619] pending state change SNK_ATTACH_WAIT -> SNK_DEBOUNCED @ 170 ms [rev3 NONE_AMS] > > [ 168.522348] VBUS on > > [ 168.568676] state change SNK_ATTACH_WAIT -> SNK_DEBOUNCED [delayed 170 ms] > > [ 168.568684] state change SNK_DEBOUNCED -> SNK_ATTACHED [rev3 NONE_AMS] > > [ 168.568688] polarity 1 > > [ 168.569867] set_auto_vbus_discharge_threshold mode:0 pps_active:n vbus:5000 ret:0 > > [ 168.570158] enable vbus discharge ret:0 > > [ 168.570161] Requesting mux state 1, usb-role 2, orientation 2 > > [ 168.570504] state change SNK_ATTACHED -> SNK_STARTUP [rev3 NONE_AMS] > > [ 168.570634] pending state change SNK_STARTUP -> SNK_DISCOVERY @ 500 ms [rev3 NONE_AMS] > > [ 169.070689] state change SNK_STARTUP -> SNK_DISCOVERY [delayed 500 ms] > > [ 169.070695] Setting voltage/current limit 5000 mV 3000 mA > > [ 169.070702] vbus=0 charge:=1 > > [ 169.072719] state change SNK_DISCOVERY -> SNK_WAIT_CAPABILITIES [rev3 NONE_AMS] > > [ 169.073145] pending state change SNK_WAIT_CAPABILITIES -> HARD_RESET_SEND @ 450 ms [rev3 NONE_AMS] > > [ 169.077162] PD RX, header: 0x2161 [1] > > [ 169.077172] PDO 0: type 0, 5000 mV, 3000 mA [E] > > [ 169.077178] PDO 1: type 0, 9000 mV, 2000 mA [] > > [ 169.077183] state change SNK_WAIT_CAPABILITIES -> SNK_NEGOTIATE_CAPABILITIES [rev2 POWER_NEGOTIATION] > > [ 169.077191] Setting usb_comm capable false > > [ 169.077753] cc=0 cc1=0 cc2=5 vbus=0 vconn=sink polarity=1 > > [ 169.077759] Requesting PDO 1: 9000 mV, 2000 mA > > [ 169.077762] PD TX, header: 0x1042 > > [ 169.079990] PD TX complete, status: 0 > > [ 169.080013] pending state change SNK_NEGOTIATE_CAPABILITIES -> HARD_RESET_SEND @ 60 ms [rev2 POWER_NEGOTIATION] > > [ 169.083183] VBUS on > > [ 169.084195] PD RX, header: 0x363 [1] > > [ 169.084200] state change SNK_NEGOTIATE_CAPABILITIES -> SNK_TRANSITION_SINK [rev2 POWER_NEGOTIATION] > > [ 169.084206] Setting standby current 5000 mV @ 500 mA > > [ 169.084209] Setting voltage/current limit 5000 mV 500 mA > > [ 169.084220] pending state change SNK_TRANSITION_SINK -> HARD_RESET_SEND @ 500 ms [rev2 POWER_NEGOTIATION] > > [ 169.260222] PD RX, header: 0x566 [1] > > [ 169.260227] Setting voltage/current limit 9000 mV 2000 mA > > [ 169.261315] set_auto_vbus_discharge_threshold mode:3 pps_active:n vbus:9000 ret:0 > > [ 169.261321] state change SNK_TRANSITION_SINK -> SNK_READY [rev2 POWER_NEGOTIATION] > > [ 169.261570] AMS POWER_NEGOTIATION finished > > > > Fixes: f0690a25a140b ("staging: typec: USB Type-C Port Manager (tcpm)") > > Signed-off-by: Badhri Jagan Sridharan > > --- > > drivers/usb/typec/tcpm/tcpm.c | 17 +++++++++++++++++ > > include/linux/usb/pd.h | 2 ++ > > 2 files changed, 19 insertions(+) > > > > diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c > > index d1d03ee90d8f..770b2edd9a04 100644 > > --- a/drivers/usb/typec/tcpm/tcpm.c > > +++ b/drivers/usb/typec/tcpm/tcpm.c > > @@ -4131,6 +4131,23 @@ static void run_state_machine(struct tcpm_port *port) > > } > > break; > > case SNK_TRANSITION_SINK: > > + /* From the USB PD spec: > > + * "The Sink Shall transition to Sink Standby before a positive or > > + * negative voltage transition of VBUS. During Sink Standby > > + * the Sink Shall reduce its power draw to pSnkStdby." > > + * > > + * This is not applicable to PPS though as the port can continue > > + * to draw negotiated power without switching to standby. > > + */ > > + if (port->supply_voltage != port->req_supply_voltage && !port->pps_data.active && > > + port->current_limit * port->supply_voltage / 1000 > PD_P_SNK_STDBY_MW) { > > + u32 stdby_ma = port->supply_voltage ? PD_P_SNK_STDBY_MW * 1000 / > > + port->supply_voltage : 0; > > Looks like unnecessary condition to me. The first condition can not be > true if port->supply_voltage == 0. So I think that should be just: > > u32 stdby_ma = PD_P_SNK_STDBY_MW * 1000 / port->supply_voltage; > > Or did I miss something? You are right. That's indeed not necessary. I was wondering whether port->supply_voltage would be 0 during the swap sequence. It doesn't seem to be. Updating in my next version - V3. Thanks Heikki ! > > > + tcpm_log(port, "Setting standby current %u mV @ %u mA", > > + port->supply_voltage, stdby_ma); > > + tcpm_set_current_limit(port, stdby_ma, port->supply_voltage); > > + } > > + fallthrough; > > case SNK_TRANSITION_SINK_VBUS: > > tcpm_set_state(port, hard_reset_state(port), > > PD_T_PS_TRANSITION); > > diff --git a/include/linux/usb/pd.h b/include/linux/usb/pd.h > > index 70d681918d01..bf00259493e0 100644 > > --- a/include/linux/usb/pd.h > > +++ b/include/linux/usb/pd.h > > @@ -493,4 +493,6 @@ static inline unsigned int rdo_max_power(u32 rdo) > > #define PD_N_CAPS_COUNT (PD_T_NO_RESPONSE / PD_T_SEND_SOURCE_CAP) > > #define PD_N_HARD_RESET_COUNT 2 > > > > +#define PD_P_SNK_STDBY_MW 2500 /* 2500 mW */ > > + > > #endif /* __LINUX_USB_PD_H */ > > -- > > 2.31.1.295.g9ea45b61b8-goog > > thanks, > > -- > heikki