Hi Matthias, On Thu, Feb 8, 2018 at 11:14 AM, Matthias Schuh <m.schuh.jr@xxxxxxxxxxxxxx> wrote: > Dear bluez-mailingslist, > > thanks for taking the time to read this: > > Setup: > > bluez-5.48, kernel 4.14.16 > > bluetoothctl and btmgmt to scan, setup and configure bt 4.2 enabled sensor nodes > > The requirement is to keep up uninterrupted scanning as long as > possible, since the sensor nodes dynamically modify their Manufacturer > Data enhancing it with sensor information. > > In general turning on discovery via bluetoothctl "scan on" delivers: > > - Information on devices in the vincinity > - Updates of devices that changed their manufacturer payload > > Monitoring the scan activity via btmgmt delivers the following loop behaviour: > > - After issueing "scan on" via bluetoothctl shows: "hci0 type 7 discovering on" > - After exactly 10 seconds I get the info: "hci0 type7 discovering off" > - After exactly 5 seconds I get the info: "hci0 type 7 discovering on" > > Analyzing the packages I scan with wireshark I noticed that I'm > missing out on several broadcast from the sensor nodes. One > explanation is that discovery seems to be automatically turned off in > the described interval. This interval is the same on different > bluetooth hardware so i guess this is somehow defined by bluez. This is because by default BlueZ employs an interleaved scanning so both LE and BR/EDR devices can be found if you don't want that you will need to use discovery filters (bluetoothctl> menu scan). > In the official documentation I could not find any clue on how to > influence this behaviour. > Is there a way to define these interval parameters? You can find the documentation here about the discovery filters here: https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/doc/adapter-api.txt#n48 > > Thanks ahead and all the best, > > Matthias > -- > To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Luiz Augusto von Dentz -- To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
