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=-6.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_PASS,T_MIXED_ES,URIBL_BLOCKED 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 DED1CC65BAE for ; Fri, 14 Dec 2018 03:09:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 89C6320879 for ; Fri, 14 Dec 2018 03:09:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=nestlabs.com header.i=@nestlabs.com header.b="LmNTazNr" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 89C6320879 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=nestlabs.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-bluetooth-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726453AbeLNDJI (ORCPT ); Thu, 13 Dec 2018 22:09:08 -0500 Received: from mail-it1-f173.google.com ([209.85.166.173]:53024 "EHLO mail-it1-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726437AbeLNDJH (ORCPT ); Thu, 13 Dec 2018 22:09:07 -0500 Received: by mail-it1-f173.google.com with SMTP id g76so6993108itg.2 for ; Thu, 13 Dec 2018 19:09:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nestlabs.com; s=google; h=mime-version:references:in-reply-to:reply-to:from:date:message-id :subject:to:cc:content-transfer-encoding; bh=oMcTET68KSzFWfrVIoQ/3IWjWFOkT82k/hMdzbkHZ+I=; b=LmNTazNr2xjQ8MVB2zk4AWnRLPB/77gMYG6/4gjAgtRiGrHu4sl4ElTw+NKssRMYiR vnUm654i5juS7DOxjDy3tLJctZOs7IkGNKGMOSlLt587ExipvF91HQyl+p9SspvKsfxr zXkJl4vso9fjoHdqjhBoc2amgII0zfibjVf9Q= 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:reply-to :from:date:message-id:subject:to:cc:content-transfer-encoding; bh=oMcTET68KSzFWfrVIoQ/3IWjWFOkT82k/hMdzbkHZ+I=; b=aXELcxg+zk7GAOKMWPjK1YyzVncmXQ043Y7M9m8DABXh84idwOSFYGWcW7UxBKUYqh tFr8l3Z9eUIAlDwrOHtHtfca2tx4LDJFdPuhIVE1fUj8ZQCruVM2s9EGIp1Dvda3p76e b9w7ElKv070J6JgZ/Kclg4gkgiVCYCCR/J8miQ3ro9NhvG1oaNCd4vyPDSEILfsYqaD7 ZHxM9FglU9x4syuda5ycO/dua4qzAKXWyeaZMWTkfFBpdvLpYLVAHHu0Z2FAp561hxE1 fJ4hWYzPiJ/Eapwv4rUedE+BV8FCw/1wFZ+Ja6CNpXPIoU5fIdV5NyyAPE8ryWpQyaMo iZGg== X-Gm-Message-State: AA+aEWbaEfzguENdN3VyNsEnv/EQQ+PIWby+BfnhdAofsLzIILxF6ZTz 0RC9oN7lgNAC84qiyNHrMpBoMzZP6PZfDjypLs/rMA== X-Google-Smtp-Source: AFSGD/UA8o66Xo//TEPrTxoBmgmBr+/aL1CN7vwJ0pJ0povbR1i/J1yZz0Jca55BjrkJSb7KShLAN4NUX2AqpIqvmDs= X-Received: by 2002:a24:3842:: with SMTP id b63mr2013402ita.19.1544756946240; Thu, 13 Dec 2018 19:09:06 -0800 (PST) MIME-Version: 1.0 References: In-Reply-To: Reply-To: yunhanw@nestlabs.com From: Yunhan Wang Date: Thu, 13 Dec 2018 19:08:54 -0800 Message-ID: Subject: Re: BLE advertisement re-enabling after ble connection goes away To: Luiz Augusto von Dentz Cc: Martin Turon , Marcel Holtmann , linux-bluetooth@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Sender: linux-bluetooth-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org Hi, Luiz Thanks for the clarification. On Thu, Dec 13, 2018 at 6:32 PM Luiz Augusto von Dentz wrote: > > Hi Yunhan, > > On Fri, Dec 14, 2018 at 4:06 AM Yunhan Wang wrote: > > > > Hi, Luiz > > > > Thanks for your reply. A little bit confused here. > > > > There is no code in bluez that directly re-enable advertisement, if > > there is, could you show the code location in bluez? > > Isn't that what the following code does: > > https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth.git/t= ree/net/bluetooth/hci_request.c#n1386 > I think this link is bluetooth code in kernel, and it is not bluez code. Now I understand you think this bluetooth code is part of bluez.. > > Bluetooth in kernel is responsible for re-enabling advertisement? The > > responsibility for re-enabling the advertising is kernel instead of > > bluez and user application code. > > Yes it is the kernel which re-enables it and it has been doing this > for a long while so I wonder why all of the a sudden we are discussing > about it. Is there a bug related to it? > I am seeing chrome os bluetooth kernel doesn't re-enable advertisement, so I wanna figure out if bluetooth in kernel or bluez user space or user application needs take this responsibility to re-enable the advertisement. Clearly you mention bluetooth kernel needs to re-enable the advertisement, I would further figure out the root cause in chrome os kernel... Thanks Best wishes Yunhan > > Thanks > > Best wishes > > Yunhan > > > > > > > > On Thu, Dec 13, 2018 at 5:21 PM Luiz Augusto von Dentz > > wrote: > > > > > > Hi Yunhan, > > > > > > You already answered your question, it is reenabled by > > > hci_req_reenable_advertising > > > > > > > > > On Fri, Dec 14, 2018 at 1:13 AM Yunhan Wang wr= ote: > > > > > > > > Hi, Luiz > > > > > > > > Rephrasing a little bit.. > > > > > > > > From what you describes, it seems Bluez is taking the responsibilit= y > > > > to reenable the advertisement in peripheral side after the previous > > > > ble connection goes > > > > away. > > > > > > > > When I did local test, the ble peripheral is using bluez, I create > > > > gatt server and ble advertisment using Bluez DBus API, when remote > > > > connection in central disconnects, I see kernel in Bluez in periphe= ral > > > > side do receive > > > > HCI_EV_DISCONN_COMPLETE event, and trigger > > > > hci_req_reenable_advertising. > > > > > > > > Maybe you can share the code location where Bluez is reenabling the > > > > advertisement after ble connection goes away? > > > > > > > > Thanks > > > > Best wishes > > > > On Thu, Dec 13, 2018 at 3:10 PM Yunhan Wang = wrote: > > > > > > > > > > Hi, Luiz > > > > > > > > > > From what you describes, it seems Bluez is taking the responsibil= ity > > > > > to reenable the advertisement after the previous ble connection g= oes > > > > > away. > > > > > > > > > > When I did local test, the ble peripheral is using bluez, I creat= e > > > > > gatt server and ble advertisment using Bluez DBus API, when remo= te > > > > > connection in central disconnects, I see kernel in Bluez do recei= ve > > > > > HCI_EV_DISCONN_COMPLETE event, and trigger > > > > > hci_req_reenable_advertising. > > > > > > > > > > Maybe you can share the code location where Bluez is reenabling t= he > > > > > advertisement after ble connection goes away? > > > > > > > > > > Thanks > > > > > Best wishes > > > > > Yunhan > > > > > > > > > > On Thu, Dec 13, 2018 at 2:30 PM Martin Turon = wrote: > > > > > > > > > > > > Hi Luiz, > > > > > > > > > > > > Is this behavior also expected on raw hci sockets? Because my = observation is that when working with raw hci over such sockets, auto-reena= ble does not occur. > > > > > > > > > > > > #define BTPROTO_HCI 1 > > > > > > #define HCI_CHANNEL_USER 1 > > > > > > > > > > > > struct sockaddr_hci shci; > > > > > > shci.hci_family =3D AF_BLUETOOTH; > > > > > > shci.hci_dev =3D s_ble_hci_device; > > > > > > shci.hci_channel =3D HCI_CHANNEL_USER; > > > > > > > > > > > > s =3D socket(PF_BLUETOOTH, SOCK_RAW, BTPROTO_HCI); > > > > > > rc =3D bind(s, (struct sockaddr *)&shci, sizeof(shci)); > > > > > > Raw socket commands might actually work but here you are using it wit= h > > > a user channel which afaik disables the stack processing. > > > > > > > > > Also, which API allows the user to control the advertising inst= ances you describe? Are they automatically created by the kernel when HCI = is sent to a raw socket to enable advertising? > > > > > > Nope you need to use the management interface to use the advertising > > > instances, or better yet use the D-Bus API: > > > > > > https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/doc/advertisi= ng-api.txt > > > > > > > > > Thanks, > > > > > > Martin > > > > > > > > > > > > _____________________________ > > > > > > Martin Turon | Google > > > > > > > > > > > > > > > > > > > > > > > > On Thu, Dec 13, 2018 at 1:49 PM Luiz Augusto von Dentz wrote: > > > > > >> > > > > > >> Hi Yunhan, > > > > > >> > > > > > >> The BlueZ API operates a bit different than HCI, it keeps re-e= nabling the advertisement if there is any instance active, but the user can= stop this by removing its instance once a connection is made, this is cons= idered more convenient than having the user to reprogram the advertisement = on every disconnection. > > > > > >> > > > > > >> On Thu, 13 Dec 2018, 18:38 Yunhan Wang > > > > >>> > > > > > >>> +Martin > > > > > >>> > > > > > >>> Hi, Luiz and Marcel > > > > > >>> > > > > > >>> When I take a look at the bluetooth code, it seems it is re-e= nabling > > > > > >>> ble advertisement after ble connection goes away. Any idea? > > > > > >>> > > > > > >>> https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/blu= etooth.git/tree/net/bluetooth/hci_event.c#n2634 > > > > > >>> https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/blu= etooth.git/tree/net/bluetooth/hci_event.c#n2712 > > > > > >>> https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/blu= etooth.git/tree/net/bluetooth/hci_request.c#n1386 > > > > > >>> https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/blu= etooth.git/tree/net/bluetooth/hci_request.c#n1734 > > > > > >>> > > > > > >>> Thanks > > > > > >>> Best wishes > > > > > >>> Yunhan > > > > > >>> On Wed, Dec 5, 2018 at 6:54 PM Yunhan Wang wrote: > > > > > >>> > > > > > > >>> > Hi, Luiz and Marcel > > > > > >>> > > > > > > >>> > May I have a question on ble behavior on BLE re-advertiseme= nt? > > > > > >>> > > > > > > >>> > According to Bluetooth spec Vol. 3 (the host volume), 9.2.4= .2, "The > > > > > >>> > device shall remain in general discoverable mode until a co= nnection is > > > > > >>> > established or the Host terminates the mode." > > > > > >>> > > > > > > >>> > There is no description on re-enabling the advertising "aft= er" > > > > > >>> > disconnection, so the responsibility for re-enabling the ad= vertising > > > > > >>> > is bluez or kernel or application code? In other words, doe= s kernel or > > > > > >>> > bluez or application would re-enable the ble advertisement = after ble > > > > > >>> > disconnection happens? > > > > > >>> > > > > > > >>> > Thanks > > > > > >>> > Best wishes > > > > > >>> > Yunhan. > > > > > > > > > > > > -- > > > Luiz Augusto von Dentz > > > > -- > Luiz Augusto von Dentz