Hi, Luiz Thanks for the clarification. On Thu, Dec 13, 2018 at 6:32 PM Luiz Augusto von Dentz <luiz.dentz@xxxxxxxxx> wrote: > > Hi Yunhan, > > On Fri, Dec 14, 2018 at 4:06 AM Yunhan Wang <yunhanw@xxxxxxxxxxxx> 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/tree/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 > > <luiz.dentz@xxxxxxxxx> 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 <yunhanw@xxxxxxxxxxxx> wrote: > > > > > > > > Hi, Luiz > > > > > > > > Rephrasing a little bit.. > > > > > > > > From what you describes, it seems Bluez is taking the responsibility > > > > 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 peripheral > > > > 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 <yunhanw@xxxxxxxxxxxx> wrote: > > > > > > > > > > Hi, Luiz > > > > > > > > > > From what you describes, it seems Bluez is taking the responsibility > > > > > to reenable the advertisement 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 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 > > > > > Yunhan > > > > > > > > > > On Thu, Dec 13, 2018 at 2:30 PM Martin Turon <mturon@xxxxxxxxxx> 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-reenable does not occur. > > > > > > > > > > > > #define BTPROTO_HCI 1 > > > > > > #define HCI_CHANNEL_USER 1 > > > > > > > > > > > > struct sockaddr_hci shci; > > > > > > shci.hci_family = AF_BLUETOOTH; > > > > > > shci.hci_dev = s_ble_hci_device; > > > > > > shci.hci_channel = HCI_CHANNEL_USER; > > > > > > > > > > > > s = socket(PF_BLUETOOTH, SOCK_RAW, BTPROTO_HCI); > > > > > > rc = bind(s, (struct sockaddr *)&shci, sizeof(shci)); > > > > > > Raw socket commands might actually work but here you are using it with > > > a user channel which afaik disables the stack processing. > > > > > > > > > Also, which API allows the user to control the advertising instances 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/advertising-api.txt > > > > > > > > > Thanks, > > > > > > Martin > > > > > > > > > > > > _____________________________ > > > > > > Martin Turon | Google > > > > > > > > > > > > > > > > > > > > > > > > On Thu, Dec 13, 2018 at 1:49 PM Luiz Augusto von Dentz <luiz.dentz@xxxxxxxxx> wrote: > > > > > >> > > > > > >> Hi Yunhan, > > > > > >> > > > > > >> The BlueZ API operates a bit different than HCI, it keeps re-enabling 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 considered more convenient than having the user to reprogram the advertisement on every disconnection. > > > > > >> > > > > > >> On Thu, 13 Dec 2018, 18:38 Yunhan Wang <yunhanw@xxxxxxxxxxxx wrote: > > > > > >>> > > > > > >>> +Martin > > > > > >>> > > > > > >>> Hi, Luiz and Marcel > > > > > >>> > > > > > >>> When I take a look at the bluetooth code, it seems it is re-enabling > > > > > >>> ble advertisement after ble connection goes away. Any idea? > > > > > >>> > > > > > >>> https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth.git/tree/net/bluetooth/hci_event.c#n2634 > > > > > >>> https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth.git/tree/net/bluetooth/hci_event.c#n2712 > > > > > >>> https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth.git/tree/net/bluetooth/hci_request.c#n1386 > > > > > >>> https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth.git/tree/net/bluetooth/hci_request.c#n1734 > > > > > >>> > > > > > >>> Thanks > > > > > >>> Best wishes > > > > > >>> Yunhan > > > > > >>> On Wed, Dec 5, 2018 at 6:54 PM Yunhan Wang <yunhanw@xxxxxxxxxxxx> wrote: > > > > > >>> > > > > > > >>> > Hi, Luiz and Marcel > > > > > >>> > > > > > > >>> > May I have a question on ble behavior on BLE re-advertisement? > > > > > >>> > > > > > > >>> > According to Bluetooth spec Vol. 3 (the host volume), 9.2.4.2, "The > > > > > >>> > device shall remain in general discoverable mode until a connection is > > > > > >>> > established or the Host terminates the mode." > > > > > >>> > > > > > > >>> > There is no description on re-enabling the advertising "after" > > > > > >>> > disconnection, so the responsibility for re-enabling the advertising > > > > > >>> > is bluez or kernel or application code? In other words, does 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
