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=-8.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT 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 B1F57C04EB8 for ; Thu, 6 Dec 2018 17:56:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 70D5120878 for ; Thu, 6 Dec 2018 17:56:31 +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="YCyJLsq4" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 70D5120878 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=roeck-us.net Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726043AbeLFR4a (ORCPT ); Thu, 6 Dec 2018 12:56:30 -0500 Received: from mail-pl1-f195.google.com ([209.85.214.195]:41153 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725898AbeLFR43 (ORCPT ); Thu, 6 Dec 2018 12:56:29 -0500 Received: by mail-pl1-f195.google.com with SMTP id u6so502410plm.8; Thu, 06 Dec 2018 09:56:29 -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=K1bJobq+6IyFctrcOVfpMg7q56Mu2MnUFGm2OlX2Z4k=; b=YCyJLsq4gS5QEzKTlyyEqt6cce7Gl4aHrtuGpncCnxWcLJZQ+wYAgbk5WmuTB01DBj uf9T9DDGA0KCy5cUjGkzjKpHDXa6nuNNb2ua5fkOlhBf957q/i4vvh6e9Mgon1c0XiWY jzGCpQjV7Sg9OOuVIG0yMzYxqagCbjZJGFYgsXdK6fE8VTEh4SfeXfpnxU3+oD19Oy0p T/ScWqPKVYMQXT87XSltQk4UMiQqTqxW04ru0n/myPMwlHePVn16kv8vxElgkTNu5F3g qWH+BZFKZRlNM3lCxGK135ZmeP+Q6kCCVtaMquXOQU0ts4RxDLz5vciAg3OioKzY5/F6 k9NQ== 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=K1bJobq+6IyFctrcOVfpMg7q56Mu2MnUFGm2OlX2Z4k=; b=LTACKg7oFOs8C10A525zTKR78lC68ztnO+D8F0P3sPR/wDZiac4YmGPsf/4K31is4C oOoK63uYbOasDvHiVoMkhGT5ErMJ2SVbQd2TWfYOfpGN2NLuaZ9cFMbJonSF6JbHM9Ud IDZbEoP6s7pA/B1iBR3uup8AVFk7biRhoAdvElNHsKboYyr8SipvZ9l1Th8aOuXVl2dg JfRROKCiJ3cpaap+OqgXfmamVxYviP7aHHTcqtVwGZ6DzsUUQ1Ry/br7h6AOVGCbkZwP U7VSbSlS55Dn/1D3yoH0KE7KIMod9ZtvjDZkYocfa5AcL+5p5Ycj/7RN03tw63/MJtuU Hq1Q== X-Gm-Message-State: AA+aEWYty244T9Q/BEpRrlncDBeobOpPTj9Z3VdP1qiVJvG3By59rukH 9o46HUVh5GTQ2czubvpn/YA= X-Google-Smtp-Source: AFSGD/WHJ1QAubSxghEiA9HWjaeYLymda5phAjeS1dT28tD0bZPDMOkbHX0qaOcHMo1QEzk4chWoVg== X-Received: by 2002:a17:902:6848:: with SMTP id f8mr28401934pln.300.1544118988671; Thu, 06 Dec 2018 09:56:28 -0800 (PST) Received: from localhost ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id a4sm993522pgv.70.2018.12.06.09.56.26 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 06 Dec 2018 09:56:27 -0800 (PST) Date: Thu, 6 Dec 2018 09:56:25 -0800 From: Guenter Roeck To: Kyle Tso Cc: heikki.krogerus@linux.intel.com, gregkh@linuxfoundation.org, badhri@google.com, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] usb: typec: tcpm: Extend the matching rules on PPS APDO selection Message-ID: <20181206175625.GA11808@roeck-us.net> References: <20181206030227.9507-1-kyletso@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181206030227.9507-1-kyletso@google.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 06, 2018 at 11:02:27AM +0800, Kyle Tso wrote: > Current matching rules ensure that the voltage range of selected Source > Capability is entirely within the range defined in one of the Sink > Capabilities. This is reasonable but not practical because Sink may not > support wide range of voltage when sinking power while Source could > advertise its capabilities in raletively wider range. For example, a > Source PDO advertising 3.3V-11V@3A (9V Prog of Fixed Nominal Voltage) > will not be selected if the Sink requires 5V-12V@3A PPS power. However, > the Sink could work well if the requested voltage range in RDOs is > 5V-11V@3A. > Maybe a graphical description would help ? Currently accepted: |--------- source -----| |----------- sink ---------------| Currently not accepted: |--------- source -----| |----------- sink ---------------| |--------- source -----| |----------- sink ---------------| |--------- source -----------------| |------ sink -------| > To improve the usability, change the matching rules to what listed > below: > a. The Source PDO is selectable if any portion of the voltage range > overlaps one of the Sink PDO's voltage range. > b. The maximum operational voltage will be the lower one between the > selected Source PDO and the matching Sink PDO. > c. The maximum power will be the maximum operational voltage times the > maximum current defined in the selected Source PDO > d. Select the Source PDO with the highest maximum power > > Signed-off-by: Kyle Tso Makes sense to me. I am a bit concerned that it might cause odd regressions, though. Did you test it with a few adapters ? With the expectation that you did, Reviewed-by: Guenter Roeck > --- > drivers/usb/typec/tcpm/tcpm.c | 29 +++++++++++++++++------------ > 1 file changed, 17 insertions(+), 12 deletions(-) > > diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c > index 3620efee2688..3001df7bd602 100644 > --- a/drivers/usb/typec/tcpm/tcpm.c > +++ b/drivers/usb/typec/tcpm/tcpm.c > @@ -2213,7 +2213,8 @@ static unsigned int tcpm_pd_select_pps_apdo(struct tcpm_port *port) > unsigned int i, j, max_mw = 0, max_mv = 0; > unsigned int min_src_mv, max_src_mv, src_ma, src_mw; > unsigned int min_snk_mv, max_snk_mv; > - u32 pdo; > + unsigned int max_op_mv; > + u32 pdo, src, snk; > unsigned int src_pdo = 0, snk_pdo = 0; > > /* > @@ -2263,16 +2264,18 @@ static unsigned int tcpm_pd_select_pps_apdo(struct tcpm_port *port) > continue; > } > > - if (max_src_mv <= max_snk_mv && > - min_src_mv >= min_snk_mv) { > + if (min_src_mv <= max_snk_mv && > + max_src_mv >= min_snk_mv) { > + max_op_mv = min(max_src_mv, max_snk_mv); > + src_mw = (max_op_mv * src_ma) / 1000; > /* Prefer higher voltages if available */ > if ((src_mw == max_mw && > - min_src_mv > max_mv) || > + max_op_mv > max_mv) || > src_mw > max_mw) { > src_pdo = i; > snk_pdo = j; > max_mw = src_mw; > - max_mv = max_src_mv; > + max_mv = max_op_mv; > } > } > } > @@ -2285,14 +2288,16 @@ static unsigned int tcpm_pd_select_pps_apdo(struct tcpm_port *port) > } > > if (src_pdo) { > - pdo = port->source_caps[src_pdo]; > - > - port->pps_data.min_volt = pdo_pps_apdo_min_voltage(pdo); > - port->pps_data.max_volt = pdo_pps_apdo_max_voltage(pdo); > - port->pps_data.max_curr = > - min_pps_apdo_current(pdo, port->snk_pdo[snk_pdo]); > + src = port->source_caps[src_pdo]; > + snk = port->snk_pdo[snk_pdo]; > + > + port->pps_data.min_volt = max(pdo_pps_apdo_min_voltage(src), > + pdo_pps_apdo_min_voltage(snk)); > + port->pps_data.max_volt = min(pdo_pps_apdo_max_voltage(src), > + pdo_pps_apdo_max_voltage(snk)); > + port->pps_data.max_curr = min_pps_apdo_current(src, snk); > port->pps_data.out_volt = > - min(pdo_pps_apdo_max_voltage(pdo), port->pps_data.out_volt); > + min(port->pps_data.max_volt, port->pps_data.out_volt); > port->pps_data.op_curr = > min(port->pps_data.max_curr, port->pps_data.op_curr); > } > -- > 2.20.0.rc2.403.gdbc3b29805-goog >