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=-2.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 16A21C3F2CD for ; Thu, 5 Mar 2020 13:57:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DE77820848 for ; Thu, 5 Mar 2020 13:57:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="MDxSg9cE" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726358AbgCEN5m (ORCPT ); Thu, 5 Mar 2020 08:57:42 -0500 Received: from mail-wr1-f49.google.com ([209.85.221.49]:33352 "EHLO mail-wr1-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726300AbgCEN5m (ORCPT ); Thu, 5 Mar 2020 08:57:42 -0500 Received: by mail-wr1-f49.google.com with SMTP id x7so7157841wrr.0 for ; Thu, 05 Mar 2020 05:57:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-transfer-encoding:content-language; bh=F+r0wTvmPFxz4yHrWQPROI0nReD205HCjjqgusQeKxo=; b=MDxSg9cEHpfqDTQnA91aApBNwE3vJ2gj6FZE42UytrraTYt1psuxEUimZbs7zbMHCh pG2lsw192cvpLc056JLFuaFHO2RhA45fyeYvOGE8l/nGEgXnyPWONHUQozU+SYniXryy tfHaGLp6Uf8aGlzTxUY28FSP7wLLW2wHMaPo5oiSH3Y6mXlHnJ58AbWlsaIiPrTG8sK/ onj0wHYWI07uWkVgTYw9Dq0WV6zPHEoSKBcZsywMvAo9lR4H/P2GyLg9Ah539tlswJP8 a8uCvNZVtFfFMd638BCfekDO1I5PkR5PIg8LGh2v6R/ttENn1PGbtypNfiBSBLOdyNKK 2Vvw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding :content-language; bh=F+r0wTvmPFxz4yHrWQPROI0nReD205HCjjqgusQeKxo=; b=sOCB9NtPp0VcKE5Msp1g7ZzwuSxoFE8oYqz+/kZSohXwhLSOB5FV6CUMw6iNz+KN/j xjDLzeTYMPXN0EaSL2I4rya1Nrou/3d50VaYLt4zcYv4CMzxt+azp/D0R/0NTle/uFHv qJyrSgdU2jt13mCyW7jSffYFr4BVAWt3pmMt5kUxSz3DkiN1y0Bhpbb0ax1fOxpbZNJA NHZu/6Bpg12/GLVpZVRZ/svzcJffpfJOa6vfv3Uqve8WuYOgKjFQRYzQZON1VRfBsFY4 3eJaBPjkhNqd9wk5j0IFWK0yZv1X/pu4FthQlUCMyl49ziqC7+4N51vLllesHPt2FzFK lxgg== X-Gm-Message-State: ANhLgQ0yBHjJs6G+dWjIC9nAAeRehzCDqc/+YdWIPySX7rOEKCZOKDSE WsIZ5ivzvIE3xD4/z1YaeB0o1sWdNCRO7A== X-Google-Smtp-Source: ADFU+vvOWNxU6HsxdedlG47P0kKdKegx2LLR86hwGXHe+h22OfHcmPFL+MtwCGTeUIC+wQaNI9ukhQ== X-Received: by 2002:a05:6000:4a:: with SMTP id k10mr9925942wrx.381.1583416660434; Thu, 05 Mar 2020 05:57:40 -0800 (PST) Received: from ?IPv6:2a02:1811:e422:ad00:5027:3352:e346:d5f0? (ptr-eiyd620mf51u7z4p88g.18120a2.ip6.access.telenet.be. [2a02:1811:e422:ad00:5027:3352:e346:d5f0]) by smtp.gmail.com with ESMTPSA id c14sm30803621wro.36.2020.03.05.05.57.38 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 05 Mar 2020 05:57:39 -0800 (PST) Subject: Re: Precise time synchronization via wifi interface (intel AX201 iwlwifi driver) To: =?UTF-8?Q?Toke_H=c3=b8iland-J=c3=b8rgensen?= , linux-wireless@vger.kernel.org, linuxwifi@intel.com References: <032f07e2-2771-619b-52b4-a25c8cd10f86@gmail.com> <87r1y72g60.fsf@toke.dk> From: Wei Liu Message-ID: <627ba0df-e4c6-7fe6-0d1a-e3d77d35c564@gmail.com> Date: Thu, 5 Mar 2020 14:57:37 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <87r1y72g60.fsf@toke.dk> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org Hi Toke, Yes, it is challenging, but IEEE802.1AS already takes consideration of IEEE802.11 MAC. So I count on the standardization to take care of the challenge :) Point being that the Intel AX201 card claims Timesync feature (https://www.mouser.com/pdfDocs/wi-fi-6-ax201-module-brief.pdf), which is based on IEEE802.1AS. So there must be some way to run gptp like application on the AX201 intel card. I appreciate any help here if someone has relevant experiences. Best, Wei On 3/5/2020 12:29 PM, Toke Høiland-Jørgensen wrote: > Wei Liu writes: > >> Hi, >> >> I am trying to achieve precise time synchronization via wifi >> interface. > Erm, good luck with that? :) > > You do realise that there's a whole bunch of stuff going on below the > driver level (listen-before-send, etc) that makes 'precise' timing (as > in microsecond-accuracy like ptp)... shall we just say challenging? > > -Toke >